function login(){

		if (login.Username.value=="")
		{
			alert ("对不起，请输入用户帐号！");
			login.Username.focus();
			return false;
		}


    var Username=document.login.Username.value;
    var check_Username = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz1234567890-";
    var i;
    for (i=0;i<Username.length;i++)
    
		if (check_Username.indexOf(Username.charAt(i))==-1) 
        {
		alert("用户帐号只能由字母和数字构成，长度在3-15位之间。");
		document.login.Username.focus();
		return false;
    	}
    	
		if ( login.Username.value.length < 3)
		{
			alert("对不起，用户帐号不能少于3位");
			login.Username.focus();
			return false;
		}

		if ( login.Username.value.length > 15)
		{
			alert("对不起，用户帐号不能多于15位");
			login.Username.focus();
			return false;
		}

 
		if (login.Password.value=="")
		{
			alert ("对不起，请输入登录密码！");
			login.Password.focus();
			return false;
		}
		
    var Password=document.login.Password.value;
    var check_Password = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz1234567890-";
    var i;
    for (i=0;i<Password.length;i++)
    
  		if (check_Password.indexOf(Password.charAt(i))==-1) 
        {
		alert("登录密码只能由字母和数字构成，长度在5-15位之间。");
		document.login.Password.focus();
		return false;
    	}		

		if ( login.Password.value.length < 5)
		{
			alert("对不起，密码长度不能少于5位！");
			login.Password.focus();
			return false;
		}

		if ( login.Password.value.length > 15)
		{
			alert("对不起，密码长度不能超过15位！");
			login.Password.focus();
			return false;
		}

return true;
}

var spam_page_url = window.location.href;
if ( spam_page_url.indexOf("cache.baidu.com") != -1) 
{
top.location="http://www.cn-dns.com/";
}