js:關於window.onload

下圖來自:http://www.cnblogs.com/wsun/p/3916487.htmljavascript

輸入圖片說明

示例1

<html>
    <head>
        <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
    </head>
    <body>
        <h1> heading 1</h1>
        <h1> heading 2</h1>
        <h1> heading 3</h1>
        <script>
            window.onload = function()  { alert("text1");}; 
        </script>

        <script>
            window.onload = function()  { alert("text2");}; 
        </script>
    </body>
</html>

或者:html

<html>
    <head>
        <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
    </head>
    <body>
        <h1> heading 1</h1>
        <h1> heading 2</h1>
        <h1> heading 3</h1>
        <script>
            window.onload = function()  { alert("text1");}; 
            window.onload = function()  { alert("text2");}; 
        </script>
    </body>
</html>

瀏覽器打開時只會執行alert("text2");java

示例2

此次在外部文件裏使用window.load:瀏覽器

test.js:ui

window.load = function() {
    alert("text3");
};

html:code

<html>
    <head>
        <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
    </head>
    <body>
        <h1> heading 1</h1>
        <h1> heading 2</h1>
        <h1> heading 3</h1>
        <script type="text/javascript" src="test.js"></script>
        <script>
            window.onload = function()  { alert("text1");}; 
            window.onload = function()  { alert("text2");}; 
        </script>
    </body>
</html>

或者:htm

<html>
    <head>
        <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
    </head>
    <body>
        <h1> heading 1</h1>
        <h1> heading 2</h1>
        <h1> heading 3</h1>
        <script>
            window.onload = function()  { alert("text1");}; 
            window.onload = function()  { alert("text2");}; 
        </script>
        <script type="text/javascript" src="test.js"></script>
    </body>
</html>

瀏覽器打開時只會執行alert("text2");blog

因此外部文件中使用window.load是沒有效果的。圖片

能夠用下面的html驗證:ip

<html>
    <head>
        <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
    </head>
    <body>
        <h1> heading 1</h1>
        <h1> heading 2</h1>
        <h1> heading 3</h1>
		<script type="text/javascript" src="./test.js"></script>
    </body>
</html>

結果是沒有alert被執行。

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