function bookcheack(){
	var form=document.mainform;

	if (form.b_name.value.replace(/ /g,"")==""){
		alert("您的姓名不能为空");
		form.b_name.focus();
		return false;
		}
		if (form.b_name.value.replace(/ /g,"").length > 20 ){
		alert("您的姓名太长了吧");
		form.b_name.focus();
		return false;
		}
	if (form.b_email.value.replace(/ /g,"").length > 40 ){
		alert("您的Email太长了吧");
		form.b_email.focus();
		return false;
		}
	
	if (form.phone.value.replace(/ /g,"").length > 30 ){
		alert("您的电话太长了吧");
		form.phone.focus();
		return false;
		}
	
	if (form.b_conter.value.replace(/ /g,"")==""){
		alert("内容不能为空");
		form.b_conter.focus();
		return false;
		}
		else if (form.b_conter.value.replace(/ /g,"").length < 3){
		alert("内容太少了吧，你这是刷屏的吗？\n\n呵呵，请重新输入你的留言内容。");
		form.b_conter.focus();
		return false;
		}
		if (form.phone.value.replace(/ /g,"").length > 3000 ){
		alert("留言内容太长了吧");
		form.phone.focus();
		return false;
		}
			
return true;				
}