function book(){
		if(form1.title.value=="")
	{
		lbltitle.innerHTML = "留言主题不能为空！";
		form1.title.focus();
		return false;
	}
	else
	{
		lbltitle.innerHTML = "";
	}

	if(form1.username.value=="")
	{
		lbluser.innerHTML = "姓名不能为空！";
		form1.username.focus();
		return false;
	}
	else
	{
		lbluser.innerHTML = "";
	}
						
	if(form1.tel.value=="")
	{
		lbltel.innerHTML = "请填写手机号码！";
		form1.tel.focus();
		return false;
	}	
	else
	{
		lbltel.innerHTML = "";
	}	
	
	if(form1.add.value=="")
	{
		lbladd.innerHTML = "请填写详细地址！";
		form1.add.focus();
		return false;
	}
	else
	{
		lbladd.innerHTML = "";
	}
     
	 if(form1.txt_check.value=="")
	{
		lblcheck.innerHTML = "请填写验证码！";
		form1.check.focus();
		return false;
	}
	else
	{
		lblcheck.innerHTML = "";
	}

	
	return true;
	
}