JS的with语句的简单应用

例一：
<html>
  <head>
    <base href="<%=basePath%>">

    <title>登录页面</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">
	<!--
	<link rel="stylesheet" type="text/css" href="styles.css">
	-->

  <script type="text/javascript">
  	function RegisterSubmit(){ 
 	//获取整个name为Register的form对象
  		with(document.Register){
  			var loginname=username.value;
  			var loginpasswd=passwd.value;
  			if(loginname==null || loginname==""){
  				alert("请填写用户名");
  			}else if(loginpasswd==null || loginpasswd==""){
  				alert("请填写密码");
  			}else{
  				document.Register.submit();
  			}
  		}
  	}
  </script>
  </head>  
  <body>
    <form action="servlet/LoginServlet" name="Register" method="post">
    	<center>
    	<table typle="text-align:cunter" width="590" border="0" bgcolor="#8FBC8F">
    		<tr><td><p align="right">用户名：</p></td>
    		    <td align="left"><input type="text" name="username" style="width:120px"/></td>
    		</tr>
    		<tr><td><p align="right">密  码：</p></td>
    		    <td align="left"><input type="password" name="passwd" style="width:120px"/></td>
    		</tr>
    		<tr rowspan="2">
    			<td align="right"><input type="button" value="提交" onclick="RegisterSubmit()"/> </td>
    			<td align="left"><input type="reset" value="重置"/></td>
    		</tr>
    	</table>
    	</center>
    </form>
  </body>
</html>
例二：
<script language="javascript"> 
<!-- 
function Lakers() { 
this.name = "kobe bryant"; 
this.age = "28"; 
this.gender = "boy"; 
} 
var people=new Lakers(); 
with(people) 
{ 
var str = "姓名: " + name + "<br>"; 
str += "年龄：" + age + "<br>"; 
str += "性别：" + gender; 
document.write(str); 
} 
//--> 
</script>