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【JavaScript】筆記01——Making Stuff Happen???

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While, generally speaking, HTML is for content and CSS is for presentation, JavaScript is for interactivity.

1、從HTML到JavaScript,像下面這樣:

<!DOCTYPE html>
<html>
    <head>
        <meta charset="UTF-8">
        <title></title>
    </head>
    <body>
        <script>
            alert("Hello, world.");
        </script>
</body> </html>

alert的意思是警告,類似於message. 效果上就是彈出一個對話框。

2、引用外部的.js文件

<!DOCTYPE html>
<html>
    <head>
        <meta charset="UTF-8">
        <title></title>
    </head>
    <body>
        <script src="script.js"></script>
</body> </html>

script.js

alert("Hello, world.");

3、在瀏覽器Console中運行JavaScript代碼,Chrome進入Console的快捷鍵是F12

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4、在正式開始學習前,需要強調的是:

A browser then runs JavaScript line-by-line, starting at the top of the file or script element and finishing at the bottom (unless you tell it to go elsewhere).

5、詢問用戶姓氏的小程序

<!DOCTYPE html>
<html>
    <head>
        <meta charset="UTF-8">
        <title></title>
    </head>
    <body>
        <script type="text/javascript">
            var surname = prompt(‘Greetings friend, may I enquire as to your surname?‘);
        </script>
    </body>
</html>

通過瀏覽器運行這段代碼,將跳出一個“小盒子”,詢問你的姓氏。

6、變量類似於一個“盒子”,我們利用它來儲存數據;它具有“名”和“值”。

聲明(Declaration)

var surname;
var age;

初始化(Initialization)

var name = "Tom";

賦值(assignment)

name = "Andy";
age = 43;

【JavaScript】筆記01——Making Stuff Happen???