var dollar=7.3572;//default 
dollar=6.8318;
function jisuan(num){
	if(num==1)
	{
		var a1 = document.form2.meiyuan.value;
		if(!isNaN(a1)){
		var tmp = a1 * dollar / 31.1035;
		document.form2.meiyuan2.value = Math.round(parseFloat(tmp)*100)/100;
		}else{	alert("无效字符，必须数字！");	}
		
	}else
	{
		var a2 = document.form2.meiyuan.value;
		if(!isNaN(a2)){
		tmp = a2 / dollar * 31.1035;
		document.form2.meiyuan2.value = Math.round(parseFloat(tmp)*100)/100;
		}else{alert("无效字符，必须数字！");}
	}
}
function checkform()
{
	var obj=document.formL;
	if(obj.username.value=="")
	{
		alert("请输入用户名");
		return false;
	}
	if(obj.password.value=="")
	{
		alert("请输入密码");
		return false;
	}
	if(obj.yzm.value=="")
	{
		alert("请输入验证码");
		return false;
	}
}