function check_form(form)
{
	var reg_user = /^[a-zA-Z0-9_]{4,20}$/;
	if(form.user.value == "")
	{
		alert("请填写用户名.");
		form.user.focus();
		return false;
	}
	if(!reg_user.test(form.user.value))
	{
		alert("您所填写的用户名不符合本站要求,(4-20位,a-z,0-9,_).");
		form.user.focus();
		return false;
	}
	var reg_mail = /^[a-zA-Z0-9_\-\.]{1,}@[a-zA-Z0-9\-]{2,}\.[a-zA-Z.\.]{2,}$/;
	/*
	if(form.mail.value == "")
	{
		alert("请输入邮箱.");
		form.mail.focus();
		return false;
	}
	if(!reg_mail.test(form.mail.value))
	{
		alert("请输入正确的邮箱.");
		form.mail.focus();
		return false;
	}
	*/
	if(form.mail.value != "")
	{
		if(!reg_mail.test(form.mail.value))
		{
		alert("请输入正确的邮箱.");
		form.mail.focus();
		return false;
		}
	}
	if(form.password.value == "")
	{
		alert("请输入密码.");
		form.password.focus();
		return false;
	}
	if(form.password.value.length < 6 )
	{
		alert("您所填写的密码过短,应该在 6-20 位之间.");
		form.password.focus();
		return false;
	}
	var repassword = form.repassword.value;
	if(form.password.value != repassword)
	{
		alert("您两次输入的密码不一致.");
		form.password.focus();
		return false;
	}
	
}

/*显示消息*/
function show_msg(str_text,text_box)
{
	text_box.style.color	=	"#ff0000";
	text_box.innerHTML		=	str_text;
}

/*验证用户名*/
function check_user(form)
{
	show_msg("　正在验证,请稍等...",document.all.msg_box);
	var value = get_xml_value(url + "person_center/register/action.php",'POST',"act=checkuser&user=" + form.user.value);
	show_msg(value,document.all.msg_box);
}