freeCodeCamp/curriculum/challenges/chinese/02-javascript-algorithms-and-data-structures/basic-javascript/logical-order-in-if-else-statements.md

---
id: 5690307fddb111c6084545d7
challengeType: 1
videoUrl: 'https://scrimba.com/c/cwNvMUV'
forumTopicId: 18228
title: if else 语句中的逻辑顺序
---

## Description
<section id='description'>
<code>if</code>、<code>else if</code>语句中代码的执行顺序是很重要的。
在条件判断语句中，代码的执行顺序是从上到下，所以你需要考虑清楚先执行哪一句，后执行哪一句。
这有两个例子。
第一个例子：

```js
function foo(x) {
  if (x < 1) {
    return "Less than one";
  } else if (x < 2) {
    return "Less than two";
  } else {
    return "Greater than or equal to two";
  }
}
```

第二个例子更改了代码的执行顺序：

```js
function bar(x) {
  if (x < 2) {
    return "Less than two";
  } else if (x < 1) {
    return "Less than one";
  } else {
    return "Greater than or equal to two";
  }
}
```

这两个函数看起来几乎一模一样，我们传一个值进去看看它们有什么区别。

```js
foo(0) // "Less than one"
bar(0) // "Less than two"
```

</section>

## Instructions
<section id='instructions'>
更改函数的逻辑顺序以便通过所有的测试用例。
</section>

## Tests
<section id='tests'>

```yml
tests:
  - text: <code>orderMyLogic(4)</code>应该返回 "Less than 5"。
    testString: assert(orderMyLogic(4) === "Less than 5");
  - text: <code>orderMyLogic(6)</code>应该返回 "Less than 10"。
    testString: assert(orderMyLogic(6) === "Less than 10");
  - text: <code>orderMyLogic(11)</code>应该返回 "Greater than or equal to 10"。
    testString: assert(orderMyLogic(11) === "Greater than or equal to 10");

```

</section>

## Challenge Seed
<section id='challengeSeed'>

<div id='js-seed'>

```js
function orderMyLogic(val) {
  if (val < 10) {
    return "Less than 10";
  } else if (val < 5) {
    return "Less than 5";
  } else {
    return "Greater than or equal to 10";
  }
}

// Change this value to test
orderMyLogic(7);
```

</div>



</section>

## Solution
<section id='solution'>


```js
function orderMyLogic(val) {
  if(val < 5) {
    return "Less than 5";
  } else if (val < 10) {
    return "Less than 10";
  } else {
    return "Greater than or equal to 10";
  }
}
```

</section>