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870 lines
32 KiB
Markdown
编写你的第一行 HTML 代码，来帮助蝙蝠侠写一封情书
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======
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在一个美好的夜晚，你的肚子拒绝消化你在晚餐吃的大块披萨，所以你不得不在睡梦中冲进洗手间。
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在浴室里，当你在思考为什么会发生这种情况时，你听到一个来自通风口的低沉声音：“嘿，我是蝙蝠侠。”
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这时，你会怎么做呢？
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在你恐慌并处于关键时刻之前，蝙蝠侠说：“我需要你的帮助。我是一个超级极客，但我不懂 HTML。我需要用 HTML 写一封情书，你愿意帮助我吗？”
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谁会拒绝蝙蝠侠的请求呢，对吧？所以让我们用 HTML 来写一封蝙蝠侠的情书。
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### 你的第一个 HTML 文件
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HTML 网页与你电脑上的其它文件一样。就同一个 .doc 文件以 MS Word 打开，.jpg 文件在图像查看器中打开一样，一个 .html 文件在浏览器中打开。
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那么，让我们来创建一个 .html 文件。你可以在 Notepad 或其它任何编辑器中完成此任务，但我建议使用 VS Code。[在这里下载并安装 VS Code][2]。它是免费的，也是我唯一喜欢的微软产品。
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在系统中创建一个目录，将其命名为 “HTML Practice”（不带引号）。在这个目录中，再创建一个名为 “Batman's Love Letter”（不带引号）的目录，这将是我们的项目根目录。这意味着我们所有与这个项目相关的文件都会在这里。
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打开 VS Code，按下 `ctrl+n` 创建一个新文件，按下 `ctrl+s` 保存文件。切换到 “Batman's Love Letter” 文件夹并将其命名为 “loveletter.html”，然后单击保存。
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现在，如果你在文件资源管理器中双击它，它将在你的默认浏览器中打开。我建议使用 Firefox 来进行 web 开发，但 Chrome 也可以。
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让我们将这个过程与我们已经熟悉的东西联系起来。还记得你第一次拿到电脑吗？我做的第一件事是打开 MS Paint 并绘制一些东西。你在 Paint 中绘制一些东西并将其另存为图像，然后你可以在图像查看器中查看该图像。之后，如果要再次编辑该图像，你在 Paint 中重新打开它，编辑并保存它。
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我们目前的流程非常相似。正如我们使用 Paint 创建和编辑图像一样，我们使用 VS Code 来创建和编辑 HTML 文件。就像我们使用图像查看器查看图像一样，我们使用浏览器来查看我们的 HTML 页面。
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### HTML 中的段落
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我们有一个空的 HTML 文件，以下是蝙蝠侠想在他的情书中写的第一段。
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“After all the battles we fought together, after all the difficult times we saw together, and after all the good and bad moments we’ve been through, I think it’s time I let you know how I feel about you.”
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复制这些到 VS Code 中的 loveletter.html。单击 “View -> Toggle Word Wrap (alt+z)” 自动换行。
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保存并在浏览器中打开它。如果它已经打开，单击浏览器中的刷新按钮。
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瞧！那是你的第一个网页！
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我们的第一段已准备就绪，但这不是在 HTML 中编写段落的推荐方法。我们有一种特定的方法让浏览器知道一个文本是一个段落。
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如果你用 `<p>` 和 `</p>` 来包裹文本，那么浏览器将识别 `<p>` 和 `</p>` 中的文本是一个段落。我们这样做：
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```
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<p>After all the battles we fought together, after all the difficult times we saw together, after all the good and bad moments we've been through, I think it's time I let you know how I feel about you.</p>
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```
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通过在 `<p>` 和 `</p>`中编写段落，你创建了一个 HTML 元素。一个网页就是 HTML 元素的集合。
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让我们首先来认识一些术语：`<p>` 是开始标签，`</p>` 是结束标签，“p” 是标签名称。元素开始和结束标签之间的文本是元素的内容。
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### “style” 属性
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在上面，你将看到文本覆盖屏幕的整个宽度。
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我们不希望这样。没有人想要阅读这么长的行。让我们设定段落宽度为 550px。
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我们可以通过使用元素的 `style` 属性来实现。你可以在其 `style` 属性中定义元素的样式（例如，在我们的示例中为宽度）。以下行将在 `p` 元素上创建一个空样式属性：
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```
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<p style="">...</p>
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```
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你看到那个空的 `""` 了吗？这就是我们定义元素外观的地方。现在我们要将宽度设置为 550px。我们这样做：
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```
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<p style="width:550px;">
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After all the battles we fought together, after all the difficult times we saw together, after all the good and bad moments we've been through, I think it's time I let you know how I feel about you.
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</p>
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```
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我们将 `width` 属性设置为 `550px`，用冒号 `:` 分隔，以分号 `;` 结束。
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另外，注意我们如何将 `<p>` 和 `</p>` 放在单独的行中，文本内容用一个制表符缩进。像这样设置代码使其更具可读性。
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### HTML 中的列表
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接下来，蝙蝠侠希望列出他所钦佩的人的一些优点，例如：
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```
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You complete my darkness with your light. I love:
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- the way you see good in the worst things
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- the way you handle emotionally difficult situations
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- the way you look at Justice
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I have learned a lot from you. You have occupied a special place in my heart over time.
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```
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这看起来很简单。
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让我们继续，在 `</p>` 下面复制所需的文本：
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```
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<p style="width:550px;">
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After all the battles we faught together, after all the difficult times we saw together, after all the good and bad moments we've been through, I think it's time I let you know how I feel about you.
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</p>
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<p style="width:550px;">
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You complete my darkness with your light. I love:
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- the way you see good in the worse
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- the way you handle emotionally difficult situations
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- the way you look at Justice
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I have learned a lot from you. You have occupied a special place in my heart over the time.
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</p>
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```
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保存并刷新浏览器。
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哇！这里发生了什么，我们的列表在哪里？
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如果你仔细观察，你会发现没有显示换行符。在代码中我们在新的一行中编写列表项，但这些项在浏览器中显示在一行中。
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如果你想在 HTML（新行）中插入换行符，你必须使用 `<br>`。让我们来使用 `<br>`，看看它长什么样：
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```
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<p style="width:550px;">
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After all the battles we faught together, after all the difficult times we saw together, after all the good and bad moments we've been through, I think it's time I let you know how I feel about you.
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</p>
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<p style="width:550px;">
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You complete my darkness with your light. I love: <br>
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- the way you see good in the worse <br>
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- the way you handle emotionally difficult situations <br>
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- the way you look at Justice <br>
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I have learned a lot from you. You have occupied a special place in my heart over the time.
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</p>
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```
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保存并刷新：
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好的，现在它看起来就像我们想要的那样！
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另外，注意我们没有写一个 `</br>`。有些标签不需要结束标签（它们被称为自闭合标签）。
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还有一件事：我们没有在两个段落之间使用 `<br>`，但第二个段落仍然是从一个新行开始，这是因为 `<p>` 元素会自动插入换行符。
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我们使用纯文本编写列表，但是有两个标签可以供我们使用来达到相同的目的：`<ul>` and `<li>`。
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让我们解释一下名字的意思：ul 代表<ruby>无序列表<rt>Unordered List</rt></ruby>，li 代表<ruby>列表项目<rt>List Item</rt></ruby>。让我们使用它们来展示我们的列表：
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```
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<p style="width:550px;">
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After all the battles we faught together, after all the difficult times we saw together, after all the good and bad moments we've been through, I think it's time I let you know how I feel about you.
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</p>
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```
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```
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<p style="width:550px;">
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You complete my darkness with your light. I love:
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<ul>
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<li>the way you see good in the worse</li>
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<li>the way you handle emotionally difficult situations</li>
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<li>the way you look at Justice</li>
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</ul>
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I have learned a lot from you. You have occupied a special place in my heart over the time.
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</p>
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```
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在复制代码之前，注意差异部分：
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* 我们删除了所有的 `<br>`，因为每个 `<li>` 会自动显示在新行中
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* 我们将每个列表项包含在 `<li>` 和 `</li>` 之间
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* 我们将所有列表项的集合包裹在 `<ul>` 和 `</ul>` 之间
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* 我们没有像 `<p>` 元素那样定义 `<ul>` 元素的宽度。这是因为 `<ul>` 是 `<p>` 的子节点，`<p>` 已经被约束到 550px，所以 `<ul>` 不会超出这个范围。
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让我们保存文件并刷新浏览器以查看结果：
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你会立即注意到在每个列表项之前显示了重点标志。我们现在不需要在每个列表项之前写 “-”。
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经过仔细检查，你会注意到最后一行超出 550px 宽度。这是为什么？因为 HTML 不允许 `<ul>` 元素出现在 `<p>` 元素中。让我们将第一行和最后一行放在单独的 `<p>` 元素中：
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```
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<p style="width:550px;">
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After all the battles we faught together, after all the difficult times we saw together, after all the good and bad moments we've been through, I think it's time I let you know how I feel about you.
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</p>
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```
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```
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<p style="width:550px;">
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You complete my darkness with your light. I love:
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</p>
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```
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```
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<ul style="width:550px;">
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<li>the way you see good in the worse</li>
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<li>the way you handle emotionally difficult situations</li>
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<li>the way you look at Justice</li>
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</ul>
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```
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```
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<p style="width:550px;">
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I have learned a lot from you. You have occupied a special place in my heart over the time.
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</p>
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```
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保存并刷新。
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注意，这次我们还定义了 `<ul>` 元素的宽度。那是因为我们现在已经将 `<ul>` 元素放在了 `<p>` 元素之外。
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定义情书中所有元素的宽度会变得很麻烦。我们有一个特定的元素用于此目的：`<div>` 元素。一个 `<div>` 元素就是一个通用容器，用于对内容进行分组，以便轻松设置样式。
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让我们用 `<div>` 元素包装整个情书，并为其赋予宽度：550px 。
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```
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<div style="width:550px;">
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<p>
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After all the battles we faught together, after all the difficult times we saw together, after all the good and bad moments we've been through, I think it's time I let you know how I feel about you.
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</p>
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<p>
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You complete my darkness with your light. I love:
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</p>
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<ul>
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<li>the way you see good in the worse</li>
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<li>the way you handle emotionally difficult situations</li>
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<li>the way you look at Justice</li>
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</ul>
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<p>
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I have learned a lot from you. You have occupied a special place in my heart over the time.
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</p>
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</div>
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```
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棒极了，我们的代码现在看起来简洁多了。
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### HTML 中的标题
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到目前为止，蝙蝠侠对结果很高兴，他希望在情书上标题。他想写一个标题： “Bat Letter”。当然，你已经看到这个名字了，不是吗？:D
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你可以使用 `<h1>`、`<h2>`、`<h3>`、`<h4>`、`<h5>` 和 `<h6>` 标签来添加标题，`<h1>` 是最大的标题和最主要的标题，`<h6>` 是最小的标题。
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让我们在第二段之前使用 `<h1>` 做主标题和一个副标题：
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```
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<div style="width:550px;">
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<h1>Bat Letter</h1>
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<p>
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After all the battles we faught together, after all the difficult times we saw together, after all the good and bad moments we've been through, I think it's time I let you know how I feel about you.
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</p>
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```
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```
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<h2>You are the light of my life</h2>
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<p>
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You complete my darkness with your light. I love:
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</p>
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<ul>
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<li>the way you see good in the worse</li>
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<li>the way you handle emotionally difficult situations</li>
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<li>the way you look at Justice</li>
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</ul>
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<p>
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I have learned a lot from you. You have occupied a special place in my heart over the time.
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</p>
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</div>
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```
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保存，刷新。
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### HTML 中的图像
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我们的情书尚未完成，但在继续之前，缺少一件大事：蝙蝠侠标志。你见过是蝙蝠侠的东西但没有蝙蝠侠的标志吗？
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并没有。
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所以，让我们在情书中添加一个蝙蝠侠标志。
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在 HTML 中包含图像就像在一个 Word 文件中包含图像一样。在 MS Word 中，你到 “菜单 -> 插入 -> 图像 -> 然后导航到图像位置为止 -> 选择图像 -> 单击插入”。
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在 HTML 中，我们使用 `<img>` 标签让浏览器知道我们需要加载的图像，而不是单击菜单。我们在 `src` 属性中写入文件的位置和名称。如果图像在项目根目录中，我们可以简单地在 `src` 属性中写入图像文件的名称。
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在我们深入编码之前，从[这里][3]下载蝙蝠侠标志。你可能希望裁剪图像中的额外空白区域。复制项目根目录中的图像并将其重命名为 “bat-logo.jpeg”。
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```
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<div style="width:550px;">
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<h1>Bat Letter</h1>
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<img src="bat-logo.jpeg">
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<p>
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After all the battles we faught together, after all the difficult times we saw together, after all the good and bad moments we've been through, I think it's time I let you know how I feel about you.
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</p>
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```
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```
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<h2>You are the light of my life</h2>
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<p>
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You complete my darkness with your light. I love:
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</p>
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<ul>
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<li>the way you see good in the worse</li>
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<li>the way you handle emotionally difficult situations</li>
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<li>the way you look at Justice</li>
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</ul>
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<p>
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I have learned a lot from you. You have occupied a special place in my heart over the time.
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</p>
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</div>
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```
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我们在第 3 行包含了 `<img>` 标签。这个标签也是一个自闭合的标签，所以我们不需要写 `</img>`。在 `src` 属性中，我们给出了图像文件的名称。这个名称应与图像名称完全相同，包括扩展名（.jpeg）及其大小写。
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保存并刷新，查看结果。
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该死的！刚刚发生了什么？
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当使用 `<img>` 标签包含图像时，默认情况下，图像将以其原始分辨率显示。在我们的例子中，图像比 550px 宽得多。让我们使用 `style` 属性定义它的宽度：
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```
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<div style="width:550px;">
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<h1>Bat Letter</h1>
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<img src="bat-logo.jpeg" style="width:100%">
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<p>
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After all the battles we faught together, after all the difficult times we saw together, after all the good and bad moments we've been through, I think it's time I let you know how I feel about you.
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</p>
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```
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```
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<h2>You are the light of my life</h2>
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<p>
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You complete my darkness with your light. I love:
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</p>
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<ul>
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<li>the way you see good in the worse</li>
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<li>the way you handle emotionally difficult situations</li>
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<li>the way you look at Justice</li>
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</ul>
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<p>
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I have learned a lot from you. You have occupied a special place in my heart over the time.
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</p>
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</div>
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```
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你会注意到，这次我们定义宽度使用了 “%” 而不是 “px”。当我们在 “%” 中定义宽度时，它将占据父元素宽度的百分比。因此，100% 的 550px 将为我们提供 550px。
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保存并刷新，查看结果。
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太棒了！这让蝙蝠侠的脸露出了羞涩的微笑 :)。
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### HTML 中的粗体和斜体
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现在蝙蝠侠想在最后几段中承认他的爱。他有以下文本供你用 HTML 编写：
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“I have a confession to make
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It feels like my chest _does_ have a heart. You make my heart beat. Your smile brings a smile to my face, your pain brings pain to my heart.
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I don’t show my emotions, but I think this man behind the mask is falling for you.”
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当阅读到这里时，你会问蝙蝠侠：“等等，这是给谁的？”蝙蝠侠说：
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“这是给超人的。”
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|
||
你说：哦！我还以为是给神奇女侠的呢。
|
||
|
||
蝙蝠侠说：不，这是给超人的，请在最后写上 “I love you Superman.”。
|
||
|
||
好的，我们来写：
|
||
|
||
|
||
```
|
||
<div style="width:550px;">
|
||
<h1>Bat Letter</h1>
|
||
<img src="bat-logo.jpeg" style="width:100%">
|
||
<p>
|
||
After all the battles we faught together, after all the difficult times we saw together, after all the good and bad moments we've been through, I think it's time I let you know how I feel about you.
|
||
</p>
|
||
```
|
||
|
||
```
|
||
<h2>You are the light of my life</h2>
|
||
<p>
|
||
You complete my darkness with your light. I love:
|
||
</p>
|
||
<ul>
|
||
<li>the way you see good in the worse</li>
|
||
<li>the way you handle emotionally difficult situations</li>
|
||
<li>the way you look at Justice</li>
|
||
</ul>
|
||
<p>
|
||
I have learned a lot from you. You have occupied a special place in my heart over the time.
|
||
</p>
|
||
<h2>I have a confession to make</h2>
|
||
<p>
|
||
It feels like my chest does have a heart. You make my heart beat. Your smile brings smile on my face, your pain brings pain to my heart.
|
||
</p>
|
||
<p>
|
||
I don't show my emotions, but I think this man behind the mask is falling for you.
|
||
</p>
|
||
<p>I love you Superman.</p>
|
||
<p>
|
||
Your not-so-secret-lover, <br>
|
||
Batman
|
||
</p>
|
||
</div>
|
||
```
|
||
|
||
这封信差不多完成了，蝙蝠侠另外想再做两次改变。蝙蝠侠希望在最后段落的第一句中的 “does” 一词是斜体，而 “I love you Superman” 这句话是粗体的。
|
||
|
||
我们使用 `<em>` 和 `<strong>` 以斜体和粗体显示文本。让我们来更新这些更改：
|
||
|
||
```
|
||
<div style="width:550px;">
|
||
<h1>Bat Letter</h1>
|
||
<img src="bat-logo.jpeg" style="width:100%">
|
||
<p>
|
||
After all the battles we faught together, after all the difficult times we saw together, after all the good and bad moments we've been through, I think it's time I let you know how I feel about you.
|
||
</p>
|
||
```
|
||
|
||
```
|
||
<h2>You are the light of my life</h2>
|
||
<p>
|
||
You complete my darkness with your light. I love:
|
||
</p>
|
||
<ul>
|
||
<li>the way you see good in the worse</li>
|
||
<li>the way you handle emotionally difficult situations</li>
|
||
<li>the way you look at Justice</li>
|
||
</ul>
|
||
<p>
|
||
I have learned a lot from you. You have occupied a special place in my heart over the time.
|
||
</p>
|
||
<h2>I have a confession to make</h2>
|
||
<p>
|
||
It feels like my chest <em>does</em> have a heart. You make my heart beat. Your smile brings smile on my face, your pain brings pain to my heart.
|
||
</p>
|
||
<p>
|
||
I don't show my emotions, but I think this man behind the mask is falling for you.
|
||
</p>
|
||
<p><strong>I love you Superman.</strong></p>
|
||
<p>
|
||
Your not-so-secret-lover, <br>
|
||
Batman
|
||
</p>
|
||
</div>
|
||
```
|
||
|
||
|
||
|
||
### HTML 中的样式
|
||
|
||
你可以通过三种方式设置样式或定义 HTML 元素的外观：
|
||
|
||
* 内联样式：我们使用元素的 `style` 属性来编写样式。这是我们迄今为止使用的，但这不是一个好的实践。
|
||
* 嵌入式样式：我们在由 `<style>` 和 `</style>` 包裹的 “style” 元素中编写所有样式。
|
||
* 链接样式表：我们在具有 .css 扩展名的单独文件中编写所有元素的样式。此文件称为样式表。
|
||
|
||
让我们来看看如何定义 `<div>` 的内联样式：
|
||
|
||
```
|
||
<div style="width:550px;">
|
||
```
|
||
|
||
我们可以在 `<style>` 和 `</style>` 里面写同样的样式：
|
||
|
||
```
|
||
div{
|
||
width:550px;
|
||
}
|
||
```
|
||
|
||
在嵌入式样式中，我们编写的样式是与元素分开的。所以我们需要一种方法来关联元素及其样式。第一个单词 “div” 就做了这样的活。它让浏览器知道花括号 `{...}` 里面的所有样式都属于 “div” 元素。由于这种语法确定要应用样式的元素，因此它称为一个选择器。
|
||
|
||
我们编写样式的方式保持不变：属性（`width`）和值（`550px`）用冒号（`:`）分隔，以分号（`;`）结束。
|
||
|
||
让我们从 `<div>` 和 `<img>` 元素中删除内联样式，将其写入 `<style>` 元素：
|
||
|
||
```
|
||
<style>
|
||
div{
|
||
width:550px;
|
||
}
|
||
img{
|
||
width:100%;
|
||
}
|
||
</style>
|
||
```
|
||
|
||
```
|
||
<div>
|
||
<h1>Bat Letter</h1>
|
||
<img src="bat-logo.jpeg">
|
||
<p>
|
||
After all the battles we faught together, after all the difficult times we saw together, after all the good and bad moments we've been through, I think it's time I let you know how I feel about you.
|
||
</p>
|
||
```
|
||
|
||
```
|
||
<h2>You are the light of my life</h2>
|
||
<p>
|
||
You complete my darkness with your light. I love:
|
||
</p>
|
||
<ul>
|
||
<li>the way you see good in the worse</li>
|
||
<li>the way you handle emotionally difficult situations</li>
|
||
<li>the way you look at Justice</li>
|
||
</ul>
|
||
<p>
|
||
I have learned a lot from you. You have occupied a special place in my heart over the time.
|
||
</p>
|
||
<h2>I have a confession to make</h2>
|
||
<p>
|
||
It feels like my chest <em>does</em> have a heart. You make my heart beat. Your smile brings smile on my face, your pain brings pain to my heart.
|
||
</p>
|
||
<p>
|
||
I don't show my emotions, but I think this man behind the mask is falling for you.
|
||
</p>
|
||
<p><strong>I love you Superman.</strong></p>
|
||
<p>
|
||
Your not-so-secret-lover, <br>
|
||
Batman
|
||
</p>
|
||
</div>
|
||
```
|
||
|
||
保存并刷新，结果应保持不变。
|
||
|
||
但是有一个大问题，如果我们的 HTML 文件中有多个 `<div>` 和 `<img>` 元素该怎么办？这样我们在 `<style>` 元素中为 div 和 img 定义的样式就会应用于页面上的每个 div 和 img。
|
||
|
||
如果你在以后的代码中添加另一个 div，那么该 div 也将变为 550px 宽。我们并不希望这样。
|
||
|
||
我们想要将我们的样式应用于现在正在使用的特定 div 和 img。为此，我们需要为 div 和 img 元素提供唯一的 id。以下是使用 `id` 属性为元素赋予 id 的方法：
|
||
|
||
```
|
||
<div id="letter-container">
|
||
```
|
||
|
||
以下是如何在嵌入式样式中将此 id 用作选择器：
|
||
|
||
```
|
||
#letter-container{
|
||
...
|
||
}
|
||
```
|
||
|
||
注意 `#` 符号。它表示它是一个 id，`{...}` 中的样式应该只应用于具有该特定 id 的元素。
|
||
|
||
让我们来应用它：
|
||
|
||
```
|
||
<style>
|
||
#letter-container{
|
||
width:550px;
|
||
}
|
||
#header-bat-logo{
|
||
width:100%;
|
||
}
|
||
</style>
|
||
```
|
||
|
||
```
|
||
<div id="letter-container">
|
||
<h1>Bat Letter</h1>
|
||
<img id="header-bat-logo" src="bat-logo.jpeg">
|
||
<p>
|
||
After all the battles we faught together, after all the difficult times we saw together, after all the good and bad moments we've been through, I think it's time I let you know how I feel about you.
|
||
</p>
|
||
```
|
||
|
||
```
|
||
<h2>You are the light of my life</h2>
|
||
<p>
|
||
You complete my darkness with your light. I love:
|
||
</p>
|
||
<ul>
|
||
<li>the way you see good in the worse</li>
|
||
<li>the way you handle emotionally difficult situations</li>
|
||
<li>the way you look at Justice</li>
|
||
</ul>
|
||
<p>
|
||
I have learned a lot from you. You have occupied a special place in my heart over the time.
|
||
</p>
|
||
<h2>I have a confession to make</h2>
|
||
<p>
|
||
It feels like my chest <em>does</em> have a heart. You make my heart beat. Your smile brings smile on my face, your pain brings pain to my heart.
|
||
</p>
|
||
<p>
|
||
I don't show my emotions, but I think this man behind the mask is falling for you.
|
||
</p>
|
||
<p><strong>I love you Superman.</strong></p>
|
||
<p>
|
||
Your not-so-secret-lover, <br>
|
||
Batman
|
||
</p>
|
||
</div>
|
||
```
|
||
|
||
HTML 已经准备好了嵌入式样式。
|
||
|
||
但是，你可以看到，随着我们包含越来越多的样式，`<style></style>` 将变得很大。这可能很快会混乱我们的主 HTML 文件。
|
||
|
||
因此，让我们更进一步，通过将 `<style>` 标签内的内容复制到一个新文件来使用链接样式。
|
||
|
||
在项目根目录中创建一个新文件，将其另存为 “style.css”：
|
||
|
||
```
|
||
#letter-container{
|
||
width:550px;
|
||
}
|
||
#header-bat-logo{
|
||
width:100%;
|
||
}
|
||
```
|
||
|
||
我们不需要在 CSS 文件中写 `<style>` 和 `</style>`。
|
||
|
||
我们需要使用 HTML 文件中的 `<link>` 标签来将新创建的 CSS 文件链接到 HTML 文件。以下是我们如何做到这一点：
|
||
|
||
```
|
||
<link rel="stylesheet" type="text/css" href="style.css">
|
||
```
|
||
|
||
我们使用 `<link>` 元素在 HTML 文档中包含外部资源，它主要用于链接样式表。我们使用的三个属性是：
|
||
|
||
* `rel`：关系。链接文件与文档的关系。具有 .css 扩展名的文件称为样式表，因此我们保留 rel=“stylesheet”。
|
||
* `type`：链接文件的类型；对于一个 CSS 文件来说它是 “text/css”。
|
||
* `href`：超文本参考。链接文件的位置。
|
||
|
||
link 元素的结尾没有 `</link>`。因此，`<link>` 也是一个自闭合的标签。
|
||
|
||
```
|
||
<link rel="gf" type="cute" href="girl.next.door">
|
||
```
|
||
|
||
如果只是得到一个女朋友，那么很容易：D
|
||
|
||
可惜没有那么简单，让我们继续前进。
|
||
|
||
这是我们 “loveletter.html” 的内容：
|
||
|
||
```
|
||
<link rel="stylesheet" type="text/css" href="style.css">
|
||
<div id="letter-container">
|
||
<h1>Bat Letter</h1>
|
||
<img id="header-bat-logo" src="bat-logo.jpeg">
|
||
<p>
|
||
After all the battles we faught together, after all the difficult times we saw together, after all the good and bad moments we've been through, I think it's time I let you know how I feel about you.
|
||
</p>
|
||
<h2>You are the light of my life</h2>
|
||
<p>
|
||
You complete my darkness with your light. I love:
|
||
</p>
|
||
<ul>
|
||
<li>the way you see good in the worse</li>
|
||
<li>the way you handle emotionally difficult situations</li>
|
||
<li>the way you look at Justice</li>
|
||
</ul>
|
||
<p>
|
||
I have learned a lot from you. You have occupied a special place in my heart over the time.
|
||
</p>
|
||
<h2>I have a confession to make</h2>
|
||
<p>
|
||
It feels like my chest <em>does</em> have a heart. You make my heart beat. Your smile brings smile on my face, your pain brings pain to my heart.
|
||
</p>
|
||
<p>
|
||
I don't show my emotions, but I think this man behind the mask is falling for you.
|
||
</p>
|
||
<p><strong>I love you Superman.</strong></p>
|
||
<p>
|
||
Your not-so-secret-lover, <br>
|
||
Batman
|
||
</p>
|
||
</div>
|
||
```
|
||
|
||
“style.css” 内容：
|
||
|
||
```
|
||
#letter-container{
|
||
width:550px;
|
||
}
|
||
#header-bat-logo{
|
||
width:100%;
|
||
}
|
||
```
|
||
|
||
保存文件并刷新，浏览器中的输出应保持不变。
|
||
|
||
### 一些手续
|
||
|
||
我们的情书已经准备好给蝙蝠侠，但还有一些正式的片段。
|
||
|
||
与其他任何编程语言一样，HTML 自出生以来（1990 年）经历过许多版本，当前版本是 HTML5。
|
||
|
||
那么，浏览器如何知道你使用哪个版本的 HTML 来编写页面呢？要告诉浏览器你正在使用 HTML5，你需要在页面顶部包含 `<!DOCTYPE html>`。对于旧版本的 HTML，这行不同，但你不需要了解它们，因为我们不再使用它们了。
|
||
|
||
此外，在之前的 HTML 版本中，我们曾经将整个文档封装在 `<html></html>` 标签内。整个文件分为两个主要部分：头部在 `<head></head>` 里面，主体在 `<body></body>` 里面。这在 HTML5 中不是必须的，但由于兼容性原因，我们仍然这样做。让我们用 `<Doctype>`, `<html>`、 `<head>` 和 `<body>` 更新我们的代码：
|
||
|
||
```
|
||
<!DOCTYPE html>
|
||
<html>
|
||
<head>
|
||
<link rel="stylesheet" type="text/css" href="style.css">
|
||
</head>
|
||
<body>
|
||
<div id="letter-container">
|
||
<h1>Bat Letter</h1>
|
||
<img id="header-bat-logo" src="bat-logo.jpeg">
|
||
<p>
|
||
After all the battles we faught together, after all the difficult times we saw together, after all the good and bad moments we've been through, I think it's time I let you know how I feel about you.
|
||
</p>
|
||
<h2>You are the light of my life</h2>
|
||
<p>
|
||
You complete my darkness with your light. I love:
|
||
</p>
|
||
<ul>
|
||
<li>the way you see good in the worse</li>
|
||
<li>the way you handle emotionally difficult situations</li>
|
||
<li>the way you look at Justice</li>
|
||
</ul>
|
||
<p>
|
||
I have learned a lot from you. You have occupied a special place in my heart over the time.
|
||
</p>
|
||
<h2>I have a confession to make</h2>
|
||
<p>
|
||
It feels like my chest <em>does</em> have a heart. You make my heart beat. Your smile brings smile on my face, your pain brings pain to my heart.
|
||
</p>
|
||
<p>
|
||
I don't show my emotions, but I think this man behind the mask is falling for you.
|
||
</p>
|
||
<p><strong>I love you Superman.</strong></p>
|
||
<p>
|
||
Your not-so-secret-lover, <br>
|
||
Batman
|
||
</p>
|
||
</div>
|
||
</body>
|
||
</html>
|
||
```
|
||
|
||
主要内容在 `<body>` 里面，元信息在 `<head>` 里面。所以我们把 `<div>` 保存在 `<body>` 里面并加载 `<head>` 里面的样式表。
|
||
|
||
保存并刷新，你的 HTML 页面应显示与之前相同的内容。
|
||
|
||
### HTML 的标题
|
||
|
||
我发誓，这是最后一次改变。
|
||
|
||
你可能已经注意到选项卡的标题正在显示 HTML 文件的路径：
|
||
|
||
|
||
|
||
我们可以使用 `<title>` 标签来定义 HTML 文件的标题。标题标签也像链接标签一样在 `<head>` 内部。让我们我们在标题中加上 “Bat Letter”：
|
||
|
||
```
|
||
<!DOCTYPE html>
|
||
<html>
|
||
<head>
|
||
<title>Bat Letter</title>
|
||
<link rel="stylesheet" type="text/css" href="style.css">
|
||
</head>
|
||
<body>
|
||
<div id="letter-container">
|
||
<h1>Bat Letter</h1>
|
||
<img id="header-bat-logo" src="bat-logo.jpeg">
|
||
<p>
|
||
After all the battles we faught together, after all the difficult times we saw together, after all the good and bad moments we've been through, I think it's time I let you know how I feel about you.
|
||
</p>
|
||
<h2>You are the light of my life</h2>
|
||
<p>
|
||
You complete my darkness with your light. I love:
|
||
</p>
|
||
<ul>
|
||
<li>the way you see good in the worse</li>
|
||
<li>the way you handle emotionally difficult situations</li>
|
||
<li>the way you look at Justice</li>
|
||
</ul>
|
||
<p>
|
||
I have learned a lot from you. You have occupied a special place in my heart over the time.
|
||
</p>
|
||
<h2>I have a confession to make</h2>
|
||
<p>
|
||
It feels like my chest <em>does</em> have a heart. You make my heart beat. Your smile brings smile on my face, your pain brings pain to my heart.
|
||
</p>
|
||
<p>
|
||
I don't show my emotions, but I think this man behind the mask is falling for you.
|
||
</p>
|
||
<p><strong>I love you Superman.</strong></p>
|
||
<p>
|
||
Your not-so-secret-lover, <br>
|
||
Batman
|
||
</p>
|
||
</div>
|
||
</body>
|
||
</html>
|
||
```
|
||
|
||
保存并刷新，你将看到在选项卡上显示的是 “Bat Letter” 而不是文件路径。
|
||
|
||
蝙蝠侠的情书现在已经完成。
|
||
|
||
恭喜！你用 HTML 制作了蝙蝠侠的情书。
|
||
|
||
|
||
|
||
### 我们学到了什么
|
||
|
||
我们学习了以下新概念：
|
||
|
||
* 一个 HTML 文档的结构
|
||
* 在 HTML 中如何写元素（`<p></p>`）
|
||
* 如何使用 style 属性在元素内编写样式（这称为内联样式，尽可能避免这种情况）
|
||
* 如何在 `<style>...</style>` 中编写元素的样式（这称为嵌入式样式）
|
||
* 在 HTML 中如何使用 `<link>` 在单独的文件中编写样式并链接它（这称为链接样式表）
|
||
* 什么是标签名称，属性，开始标签和结束标签
|
||
* 如何使用 id 属性为一个元素赋予 id
|
||
* CSS 中的标签选择器和 id 选择器
|
||
|
||
我们学习了以下 HTML 标签：
|
||
|
||
* `<p>`：用于段落
|
||
* `<br>`：用于换行
|
||
* `<ul>`、`<li>`：显示列表
|
||
* `<div>`：用于分组我们信件的元素
|
||
* `<h1>`、`<h2>`：用于标题和子标题
|
||
* `<img>`：用于插入图像
|
||
* `<strong>`、`<em>`：用于粗体和斜体文字样式
|
||
* `<style>`：用于嵌入式样式
|
||
* `<link>`：用于包含外部样式表
|
||
* `<html>`：用于包裹整个 HTML 文档
|
||
* `<!DOCTYPE html>`：让浏览器知道我们正在使用 HTML5
|
||
* `<head>`：包裹元信息，如 `<link>` 和 `<title>`
|
||
* `<body>`：用于实际显示的 HTML 页面的主体
|
||
* `<title>`：用于 HTML 页面的标题
|
||
|
||
我们学习了以下 CSS 属性：
|
||
|
||
* width：用于定义元素的宽度
|
||
* CSS 单位：“px” 和 “%”
|
||
|
||
朋友们，这就是今天的全部了，下一个教程中见。
|
||
|
||
--------------------------------------------------------------------------------
|
||
|
||
作者简介：开发者 + 作者 | supersarkar.com | twitter.com/supersarkar
|
||
|
||
-------------
|
||
|
||
via: https://medium.freecodecamp.org/for-your-first-html-code-lets-help-batman-write-a-love-letter-64c203b9360b
|
||
|
||
作者：[Kunal Sarkar][a]
|
||
译者：[MjSeven](https://github.com/MjSeven)
|
||
校对：[wxy](https://github.com/wxy)
|
||
|
||
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出
|
||
|
||
[a]:https://medium.freecodecamp.org/@supersarkar
|
||
[1]:https://www.pexels.com/photo/batman-black-and-white-logo-93596/
|
||
[2]:https://code.visualstudio.com/
|
||
[3]:https://www.pexels.com/photo/batman-black-and-white-logo-93596/
|
||
[4]:http://supersarkar.com/
|