51 lines
879 B
Markdown
51 lines
879 B
Markdown
|
---
|
||
|
|
id: 56533eb9ac21ba0edf2244a9
|
||
|
|
title: 使用賦值運算符初始化變量
|
||
|
|
challengeType: 1
|
||
|
|
videoUrl: 'https://scrimba.com/c/cWJ4Bfb'
|
||
|
|
forumTopicId: 301171
|
||
|
|
dashedName: initializing-variables-with-the-assignment-operator
|
||
|
|
---
|
||
|
|
|
||
|
|
# --description--
|
||
|
|
|
||
|
|
通常在聲明變量的時候會給變量<dfn>初始化</dfn>一個初始值。
|
||
|
|
|
||
|
|
```js
|
||
|
|
var myVar = 0;
|
||
|
|
```
|
||
|
|
|
||
|
|
創建一個名爲 `myVar` 的變量，並指定其初始值爲 `0`。
|
||
|
|
|
||
|
|
# --instructions--
|
||
|
|
|
||
|
|
通過關鍵字 `var` 定義一個變量 `a`，並且給它一個初始值 `9`。
|
||
|
|
|
||
|
|
# --hints--
|
||
|
|
|
||
|
|
應該初始化 `a` 的值爲 `9`。
|
||
|
|
|
||
|
|
```js
|
||
|
|
assert(/var\s+a\s*=\s*9(\s*;?\s*)$/.test(code));
|
||
|
|
```
|
||
|
|
|
||
|
|
# --seed--
|
||
|
|
|
||
|
|
## --after-user-code--
|
||
|
|
|
||
|
|
```js
|
||
|
|
if(typeof a !== 'undefined') {(function(a){return "a = " + a;})(a);} else { (function() {return 'a is undefined';})(); }
|
||
|
|
```
|
||
|
|
|
||
|
|
## --seed-contents--
|
||
|
|
|
||
|
|
```js
|
||
|
|
|
||
|
|
```
|
||
|
|
|
||
|
|
# --solutions--
|
||
|
|
|
||
|
|
```js
|
||
|
|
var a = 9;
|
||
|
|
```
|