function isNumberString (InString,RefString)
{
	if(InString.length==0) return (false);
	for (Count=0; Count < InString.length; Count++)  
	{
		TempChar= InString.substring (Count, Count+1);
		if (RefString.indexOf (TempChar, 0)==-1)  
		return (false);
	}
	return (true);
}
function check()
{
	var UserName=login.UserName.value;
	var Password=login.Password.value;
	var CHKCode=login.CHKCode.value;
	if(UserName=="")
	{
		alert("请输入登录名称");
		login.UserName.focus();
		return false;
	}
	if(Password=="")
	{
		alert("请输入登录密码");
		login.Password.focus();
		return false;		
	}
	if(CHKCode=="")
	{
		alert("请输入验证码");
		login.CHKCode.focus();
		return false;		
	}
	if(login.UserName.value.length<4 || login.UserName.value.length>20 || isNumberString(login.UserName.value,"abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ")!=1)
	{
		alert("帐号或密码错误，请重新输入。");
		return false;
	}
	if(login.Password.value.length<6 || login.Password.value.length>16)
	{
		alert("帐号或密码错误，请重新输入。");
		return false;
	}
	if(login.UserName.value.length<4 || login.UserName.value.length>20 || isNumberString(login.UserName.value,"abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ")!=1)
	{
		alert("帐号或密码错误，请重新输入。");
		return false;
	}
	if(login.CHKCode.value.length!=4 || isNumberString(login.CHKCode.value,"0123456789")!=1)
	{
		alert("验证码不正确，请重新输入。");
		login.CHKCode.value="";
		login.CHKCode.focus();
		return false;
	}
	function disabledSubmit(id)
	{
		var ctrl = document.getElementById(id);
		if (ctrl != null)
		{
			ctrl.disabled = true;
		}
		return false;
	}
	disabledSubmit("Submit1");
	return true;
}