---
id: 587d78b0367417b2b2512b05
title: 制作一个技术文档页面
challengeType: 14
forumTopicId: 301146
dashedName: build-a-technical-documentation-page
---

# --description--

**目标：** 构建一个功能类似于 <a href="https://technical-documentation-page.freecodecamp.rocks" target="_blank" rel="noopener noreferrer nofollow">https://technical-documentation-page.freecodecamp.rocks</a> 的应用程序

**需求：**

1. 你能看见一个 `id="main-doc"` 的 `main`元素，它包含页面的主要内容（技术文档）。
1. 在 `#main-doc` 元素内，我能看见至少 5 个 `section` 元素，每个元素都有一个 class 为 `main-section`。 应存在至少 5 个这样的元素。
1. 每个 `.main-section` 中的第一个元素应该是 `header` 元素，其中包含描述该部分主题的文本。
1. class 为 `main-section` 的每个 `section` 元素应该有一个与包含在其中的每个 `header` 的文本相对应的 `id`。 所有空格都应该被替换为下划线（例如，包含标题 “JavaScript and Java” 的 section 应有一个相应的 `id="JavaScript_and_Java"`）。
1. 所有 `.main-section` 元素总计（不是每个）包含至少 10 个 `p` 元素。
1. 所有 `.main-section` 元素总计（不是每个）包含至少 5 个 `code` 元素。
1. 所有 `.main-section` 元素总计（不是每个）包含至少 5 个 `li` 元素。
1. 你能看见一个 `id="navbar"` 的 `nav` 元素。
1. navbar 元素应包含一个 `header` 元素，其中包含描述技术文档主题的文本。
1. 此外，导航栏应包含 class 为 `nav-link` 的链接元素（`a`）。 每个 class 为 `main-section` 的元素都需要有一个。
1. `#navbar` 中的 `header` 元素必须在任何链接（`a`）之前。
1. class 为 `nav-link` 的每个元素都应该包含每个 `section` 的 `header` 文本对应的文本（例如，如果你有一个 “Hello world” 部分/标题，你的导航栏应该有一个包含文本 “Hello world” 的元素）。
1. 当你点击一个 navbar 元素时，页面应该导航到 `#main-doc` 元素的相应部分（例如，如果你点击包含文本 “Hello world” 的 `.nav-link` 元素，页面将导航到一个带有对应 header 和 id 的 `section` 元素）。
1. 在常规尺寸的设备上（笔记本电脑、台式机），带有 `id="navbar"` 的元素应该显示在屏幕左侧，并且始终对用户可见。
1. 你的技术文档应该使用至少一个媒体查询。

完成需求并通过下面的所有测试来完成这个项目。 赋予它你自己的个人风格。 编程愉快！

**注意：** 请在你的 HTML 中添加 `<link rel="stylesheet" href="styles.css">` 以链接你的样式表并应用你的 CSS

# --hints--

你应该有一个 `id` 为 `main-doc` 的 `main` 元素。

```js
const el = document.getElementById('main-doc')
assert(!!el)
```

你至少应该有 5 个 class 为 `main-section` 的 `section` 元素。

```js
const els = document.querySelectorAll('#main-doc section')
assert(els.length >= 5)
```

你所有的 `.main-section` 元素都应该是 `section` 元素。

```js
const els = document.querySelectorAll('.main-section')
els.forEach(el => {
  if (el.tagName !== 'SECTION') assert(false)
})
assert(els.length > 0)
```

你至少应该有 5 个 `.main-section` 元素，它们是 `#main-doc` 的子元素。

```js
const els = document.querySelectorAll('#main-doc .main-section')
assert(els.length >= 5)
```

每个 `.main-section` 的第一个子元素都应该是一个 `header` 元素。

```js
const els = document.querySelectorAll('.main-section')
els.forEach(el => {
  if(el.firstElementChild?.tagName !== 'HEADER') assert(false)
})
assert(els.length > 0)
```

你的 `header` 元素不应为空。

```js
const els = document.querySelectorAll('header')
els.forEach(el => {
  if (el.innerText?.length <= 0) assert(false)
})
assert(els.length > 0)
```

你所有的 `.main-section` 元素都应该有 `id`。

```js
const els = document.querySelectorAll('.main-section')
els.forEach(el => {
  if (!el.id || el.id === '') assert(false)
})
assert(els.length > 0)
```

每个 `.main-section` 都应该有一个与其第一个子元素的文本匹配的 `id`，把子元素的文本中的空格都替换为下划线（`_`）用于 id。

```js
const els = document.querySelectorAll('.main-section')
els.forEach(el => {
  const text = el.firstElementChild?.innerText?.replaceAll(' ', '_')
  if (el.id?.toUpperCase() !== text?.toUpperCase()) assert(false)
})
assert(els.length > 0)
```

在你的 `.main-section` 元素中总计应有至少 10 个 `p` 元素

```js
const els = document.querySelectorAll('.main-section p')
assert(els.length >= 10)
```

所有 `.main-section` 元素内总计应有至少 5 个 `code` 元素。

```js
const els = document.querySelectorAll('.main-section code')
assert(els.length >= 5)
```

所有 `.main-section` 元素内总计应有至少 5 个 `li` 元素。

```js
const els = document.querySelectorAll('.main-section li')
assert(els.length >= 5)
```

你应该有一个 `id` 为 `navbar` 的 `nav` 元素。

```js
const el = document.getElementById('navbar')
assert(!!el && el.tagName === 'NAV')
```

你的 `#navbar` 应该只有一个 `header` 元素。

```js
const els = document.querySelectorAll('#navbar header')
assert(els.length === 1)
```

你应该至少有一个 class 为 `nav-link` 的 `a` 元素。

```js
const els = document.querySelectorAll('a.nav-link')
assert(els.length >= 1)
```

你所有的 `.nav-link` 元素都应该是锚点（`a`）元素。

```js
const els = document.querySelectorAll('.nav-link')
els.forEach(el => {
  if (el.tagName !== 'A') assert(false)
})
assert(els.length > 0)
```

你所有的 `.nav-link` 元素都应该在 `#navbar` 中。

```js
const els1 = document.querySelectorAll('.nav-link')
const els2 = document.querySelectorAll('#navbar .nav-link')
assert(els2.length > 0 && els1.length === els2.length)
```

你应该有相同数量的 `.nav-link` 和 `.main-section` 元素。

```js
const els1 = document.querySelectorAll('.main-section')
const els2 = document.querySelectorAll('.nav-link')
assert(els1.length > 0 && els2.length > 0 && els1.length === els2.length)
```

`#navbar` 中的 `header` 元素必须在 `#navbar` 中的任何链接（`a`）之前。

```js
const navLinks = document.querySelectorAll('#navbar a.nav-link');
const header = document.querySelector('#navbar header');
navLinks.forEach((navLink) => {
  if (
    (
      header.compareDocumentPosition(navLink) &
      Node.DOCUMENT_POSITION_PRECEDING
    ) 
  ) assert(false)
});
assert(!!header)
```

每个 `.nav-link` 应该有与其相关 `section` 的 `header` 文本相对应的文本（例如，如果你有一个 “Hello world” 部分/标题，你的 `#navbar` 应该有一个 `.nav-link` 包含文本 “Hello world”）。

```js
const headerText = Array.from(document.querySelectorAll('.main-section')).map(el =>
  el.firstElementChild?.innerText?.trim().toUpperCase()
)
const linkText = Array.from(document.querySelectorAll('.nav-link')).map(el =>
  el.innerText?.trim().toUpperCase()
)
const remainder = headerText.filter(str => linkText.indexOf(str) === -1)
assert(headerText.length > 0 && headerText.length > 0 && remainder.length === 0)
```

每个 `.nav-link` 都应该有一个 `href` 属性，该属性链接到其对应的 `.main-section`（例如，如果你单击包含文本 “Hello world” 的 `.nav-link` 元素，页面导航到具有该 id 的 `section` 元素）。

```js
const hrefValues = Array.from(document.querySelectorAll('.nav-link')).map(el => el.getAttribute('href'))
const mainSectionIDs = Array.from(document.querySelectorAll('.main-section')).map(el => el.id)
const missingHrefValues = mainSectionIDs.filter(str => hrefValues.indexOf('#' + str) === -1)
assert(hrefValues.length > 0 && mainSectionIDs.length > 0 && missingHrefValues.length === 0)
```

你的 `#navbar` 元素应该始终位于视口的顶部。

```js
const el = document.getElementById('navbar')
const left1 = el?.offsetLeft
const left2 = el?.offsetLeft
assert(!!el && left1 >= -15 && left1 <= 15 && left2 >= -15 && left2 <= 15)
```

你的技术文档项目应该使用至少一个媒体查询。

```js
const htmlSourceAttr = Array.from(document.querySelectorAll('source')).map(el => el.getAttribute('media'))
const cssCheck = new __helpers.CSSHelp(document).getCSSRules('media')
assert(cssCheck.length > 0 || htmlSourceAttr.length > 0);
```

# --seed--

## --seed-contents--

```html

```

```css

```

## --solutions--

```html
<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <link rel="stylesheet" href="styles.css" />
    <title>Technical Documentation Page</title>
  </head>
  <body>
    <nav id="navbar">
      <header><br />Algebraic Concepts</header>
      <hr />
      <a href="#introduction" class="nav-link">Introduction</a><br />
      <hr />
      <a href="#definitions" class="nav-link">Definitions</a><br />
      <hr />
      <a href="#examples" class="nav-link">Examples</a><br />
      <hr />
      <a href="#solving_equations" class="nav-link">Solving Equations</a><br />
      <hr />
      <a href="#solving_equations_ii" class="nav-link">Solving Equations II</a
      ><br />
      <hr />
      <a href="#solving_equations_iii" class="nav-link">Solving Equations III</a
      ><br />
      <hr />
      <a href="#system_of_equations" class="nav-link">System of Equations</a
      ><br />
      <hr />
      <a href="#try_it_yourself!" class="nav-link">Try it Yourself!</a><br />
      <hr />
      <a href="#more_information" class="nav-link">More Information</a><br />
    </nav>
    <main id="main-doc">
      <section class="main-section" id="introduction">
        <header>Introduction</header>
        <p>
          Welcome to a basic introduction of algebra. In this tutorial, we will
          review some of the more common algebraic concepts.
        </p>
      </section>
      <section class="main-section" id="definitions">
        <header>Definitions</header>
        <p>
          To start with, let's define some of the more common terms used in
          algebra:
        </p>
        <ul>
          <li>
            <b>Variable:</b> A variable is an unknown value, usually represented
            by a letter.
          </li>
          <li>
            <b>Expression:</b> Essentially a mathematical object. For the
            purpose of this tutorial, an expression is one part of an equation.
          </li>
          <li>
            <b>Equation:</b> An equation is a mathematical argument in which two
            expressions result in the same value.
          </li>
        </ul>
      </section>
      <section class="main-section" id="examples">
        <header>Examples</header>
        <p>
          Sometimes it is easier to understand the definitions when you have a
          physical example to look at. Here is an example of the above terms.<br /><br />
          <code>x + 5 = 12 </code><br /><br />
          In this above example, we have:
        </p>
        <ul>
          <li><b>Variable:</b> The variable in the example is "x".</li>
          <li>
            <b>Expression:</b> There are two expressions in this example. They
            are "x+5" and "12".
          </li>
          <li>
            <b>Equation:</b> The entire example, "x+5=12", is an equation.
          </li>
        </ul>
      </section>
      <section class="main-section" id="solving_equations">
        <header>Solving Equations</header>
        <p>
          The primary use for algebra is to determine an unknown value, the
          "variable", with the information provided. Continuing to use our
          example from above, we can find the value of the variable "x".<br /><br />
          <code>x + 5 = 12 </code><br /><br />
          In an equation, both sides result in the same value. So you can
          manipulate the two expressions however you need, as long as you
          perform the same operation (or change) to each side. You do this
          because the goal when solving an equation is to
          <b
            >get the variable into its own expression, or by itself on one side
            of the = sign.</b
          ><br />For this example, we want to remove the "+5" so the "x" is
          alone. To do this, we can <em>subtract 5</em>, because subtraction is
          the opposite operation to addition. But remember, we have to perform
          the same operation to both sides of the equation. Now our equation
          looks like this.<br /><br />
          <code>x + 5 - 5 = 12 - 5</code><br /><br />
          The equation looks like a mess right now, because we haven't completed
          the operations. We can <b>simplify</b> this equation to make it easier
          to read by performing the operations "5-5" and "12-5". The result
          is:<br /><br />
          <code>x = 7</code><br /><br />
          We now have our solution to this equation!
        </p>
      </section>
      <section class="main-section" id="solving_equations_ii">
        <header>Solving Equations II</header>
        <p>
          Let us look at a slightly more challenging equation.<br /><br />
          <code>3x + 4 = 13</code><br /><br />
          Again we can start with subtraction. In this case, we want to subtract
          4 from each side of the equation. We will also go ahead and simplify
          with each step. So now we have:<br /><br />
          <code>3x = 9</code><br /><br />
          "3x" translates to "3*x", where the "*" symbol indicates
          multiplication. We use the "*" to avoid confusion, as the "x" is now a
          variable instead of a multiplication symbol. The opposite operation
          for multiplication is division, so we need to
          <b>divide each expression by 3</b>.<br /><br />
          <code>x = 3</code><br /><br />
          And now we have our solution!
        </p>
      </section>
      <section class="main-section" id="solving_equations_iii">
        <header>Solving Equations III</header>
        <p>
          Now we are getting in to more complex operations. Here is another
          equation for us to look at:<br /><br />
          <code>x^2 - 8 = 8</code><br /><br />
          Our very first step will be to <b>add</b> 8 to each side. This is
          different from our previous examples, where we had to subtract. But
          remember, our goal is to get the variable alone by performing opposite
          operations.<br /><br />
          <code>x^2 = 16</code><br /><br />
          But what does the "^2" mean? The "^" symbol is used to denote
          exponents in situations where superscript is not available. When
          superscript <b>is</b> available, you would see it as x<sup>2</sup>.
          For the sake of this project, however, we will use the "^" symbol.<br />
          An exponent tells you how many times the base (in our case, "x") is
          multiplied by itself. So, "x^2" would be the same as "x*x". Now the
          opposite function of multiplication is division, but we would have to
          <b>divide both sides by "x"</b>. We do not want to do this, as that
          would put an "x" on the other side of the equation. So instead, we
          need to use the root operation! For an exponent of "2", we call this
          the "square root" and denote it with "√". Our equation is now:
          <br /><br />
          <code>x = √9</code><br /><br />
          Performing a root operation by hand can be a tedious process, so we
          recommend using a calculator when necessary. However, we are lucky in
          that "9" is a
          <a href="https://en.wikipedia.org/wiki/Square_number"
            >perfect square</a
          >, so we do not need to calculate anything. Instead, we find our
          answer to be:<br /><br />
          <code>x = 3</code>
        </p>
      </section>
      <section class="main-section" id="system_of_equations">
        <header>System of Equations</header>
        <p>
          As you explore your algebra studies further, you may start to run
          across equations with more than one variable. The first such equations
          will likely look like:<br /><br />
          <code>y = 3x</code><br /><br />
          An equation like this does <b>not have one single solution</b>.
          Rather, there are a series of values for which the equation is true.
          For example, if "x=3" and "y=9", the equation is true. These equations
          are usually used to plot a graph. <br />
          Getting more complicated, though, you may be given a <b>pair</b> of
          equations. This is called a "system of equations", and CAN be solved.
          Let's look at how we do this! Consider the following system of
          equations:<br /><br />
          <code>y = 3x | y - 6 = x</code>
          A system of equations IS solvable, but it is a multi-step process. To
          get started, we need to choose a variable we are solving for. Let's
          solve for "x" first. From the second equation, we know that "x" equals
          "y - 6", but we cannot simplify that further because we do not have a
          value for "y". Except, thanks to the system of equations, we DO have a
          value for "y". We know that "y" equals "3x". So, looking at our second
          equation, we can replace "y" with "3x" because they have the same
          value. We then get:<br /><br />
          <code>3x - 6 = x</code><br /><br />
          Now we can solve for "x"! We start by adding 6 to each side.<br /><br />
          <code>3x = x + 6</code><br /><br />
          We still need to get "x" by itself, so we subtract "x" from both sides
          and get:<br /><br />
          <code>2x = 6</code><br /><br />
          If this confuses you, remember that "3x" is the same as "x+x+x".
          Subtract an "x" from that and you get "x+x", or "2x". Now we divide
          both sides by 2 and have our value for x!<br /><br />
          <code>x = 3</code><br /><br />
          However, our work is not done yet. We still need to find the value for
          "y". Let's go back to our first equation:<br /><br />
          <code>y = 3x</code><br /><br />
          We have a value for "x" now, so let's see what happens if we put that
          value in.<br /><br />
          <code>y = 3*3</code><br /><br />
          We perform the multiplication and discover that "y=9"! Our solution to
          this system of equations then is:<br /><br />
          <code>x = 3 and y = 9</code><br /><br />
        </p>
      </section>
      <section class="main-section" id="try_it_yourself!">
        <header>Try it Yourself!</header>
        <p>Coming Soon!</p>
        <p>Keep an eye out for new additions!</p>
      </section>
      <section class="main-section" id="more_information">
        <header>More Information</header>
        <p>Check out the following links for more information!</p>
        <ul>
          <li>
            <a href="https://www.wolframalpha.com/examples/mathematics/algebra/"
              >Wolfram Alpha</a
            >
            is a great source for multiple mathematic fields.
          </li>
          <li>
            <a href="https://en.wikipedia.org/wiki/Algebra"
              >Wikipedia's Algebra page</a
            >
            for more general information.
          </li>
        </ul>
      </section>
    </main>
  </body>
  <footer>
    <a href="../">Return to Project List</a> |
    <a href="https://www.nhcarrigan.com">Return to HomePage</a>
  </footer>
</html>
```

```css
* {
  background-color: #3a3240;
}
a {
  color: #92869c;
}
a:hover {
  background-color: #92869c;
  color: #3a3240;
}
#navbar {
  border-style: solid;
  border-width: 5px;
  border-color: #92869c;
  height: 100%;
  top: -5px;
  left: -5px;
  padding: 5px;
  text-align: center;
  color: #92869c
}
@media (min-width: 480px) {
  #navbar {
    position: fixed;
  }
}
main {
  margin-left: 220px;
  color: #92869c
}
header {
  font-size: 20pt;
}
code {
  background-color: #92869c;
  border-style: dashed;
  border-width: 2px;
  border-color: #92869c;
  padding: 5px;
  color: black;
}
footer {
  text-align: center;
}
```
