一、JavaScript介绍
1.JavaScript是互联网上最流行的脚本语言,这门语言可用于web和HTML,更可广泛用于服务器、PC端、移动端。
2.JavaScript脚本语言:JavaScript是一种轻量级的编程语言。JavaScript是可插入HTML页面的编程代码。JavaScript插入HTML页面后,可由所有的浏览器执行。
二、JavaScript实现
1.JavaScript用法:HTML中的脚本必须位于<script></script>标签之间。脚本可被放置在HTML页面的<body>和<head>部分中。
2.JavaScript标签:在HTML中插入JavaScript,使用<script>标签。在<script></script>之间书写代码
3.JavaScript使用限制:在HTML中,不限制脚本数量。通常会把脚本放置于<head>标签中,以不干扰页面内容。
4.代码演示
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<!DOCTYPE html> <html lang= "en" >
<head> <meta charset= "UTF-8" >
<title>Title</title>
<script>
document.write( "hello yeleven" );
</script>
</head> <body> </body> </html> |
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<!DOCTYPE html> <html lang= "en" >
<head> <meta charset= "UTF-8" >
<title>Title</title>
</head> <body> <script> document.write( "hello yeleven" );
</script> </body> </html> |
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<!DOCTYPE html> <html lang= "en" >
<head> <meta charset= "UTF-8" >
<title>Title</title>
</head> <body> <script> document.write( "hello yeleven" );
</script> <script> document.write( "hello yeleven" );
</script> </body> </html> |
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<!DOCTYPE html> <html lang= "en" >
<head> <meta charset= "UTF-8" >
<title>Title</title>
</head> <body> <script src= "myjs.js" ></script>
</body> </html> |
三、JavaScript输出
1.JavaScript通常用来操作HTML
2.文档输出:document.write("<p>This is my first JavaScript</p>");
3.实例
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<!DOCTYPE html> <html lang= "en" >
<head> <meta charset= "UTF-8" >
<title>Title</title>
</head> <body> <p id= "pid" >Hello</p>
<script>
document.getElementById( "pid" ).innerHTML= "yeleven" ;
</script>
</body> </html> |
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<!DOCTYPE html> <html lang= "en" >
<head> <meta charset= "UTF-8" >
<title>Title</title>
</head> <body> <script> document.write( "<h1>标签h1</h1>" );
</script> </body> </html> |
本文转自yeleven 51CTO博客,原文链接:http://blog.51cto.com/11317783/1791501