js的变量的定义的讲解

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1、常用的javascript脚本
jquery dojo ext js

<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()

+":"+request.getServerPort()+path+"/";
%>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
    <base href="<%=basePath%>">

    <title>My JSP 'index.jsp' starting page</title>
<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">

<script type="text/javascript">
    //document.write("我爱你");
    //这是声明变量
    var i = 2;
    var i,j;
    var notNull = true;
    m = 10;
    /*alert(j);//结果是undefined
    alert(i);
    alert(m);
alert(k);//这样会报错k没有定义
*/

    var s = 3;
    //alert(s);
    s = false;
    //alert(s);
    //全局变量、局部变量
    var globe = false;//全局变量
    function test()
    {
      var global = 'asd';//局部变量
      i = 123;//这是全局变量
      document.write(globe+"<br/>");
      document.write(global+"<br/>");
    }
    document.write(globe+"<br/>");
    document.write(global);


    </script>
//这是引入外部的js
   
</head>

<body>

<a href="#" onclick="test();">点击</a>


</body>
</html>