function CheckUsername(str){return /^[A-Za-z](\w){1,31}$/.test(str);}
function CheckNickname(str){return /^([\w\u4e00-\u9fa5]){1,16}$/.test(str);}
function CheckPassword(str){return /^[^\u4e00-\u9fa5]{6,}$/.test(str);}
function CheckEmail(str){return /^\w+([-+.]\w+)*@\w+([-.]\w+)*\.\w+([-.]\w+)*$/.test(str);}
function CheckQQ(str){return /^[0-9]{5,10}$/.test(str);}
function CheckIdentifyingCode(str){return /^([A-Za-z0-9]){8}$/.test(str);}

function ValidateElement(elem,validateFunc,content){
	var value=elem.value,errMessage;
	if(!validateFunc(value)){
		errMessage=content+"格式错误，请检查后重新输入。";
	}else{
		return true;
	}
	alert(errMessage);
	elem.focus();
	return false;
}
function ValidateUsernameElement(elem){
	return ValidateElement(elem,CheckUsername,"用户名");
}
function ValidatePasswordElement(elem){
	return ValidateElement(elem,CheckPassword,"密码");
}

function ValidateMessageLeaverElement(elem){
	var value=elem.value,errMessage;
	if(!(value.length==0||CheckNickname(value))){
		errMessage="留言用户名只能包含汉字，英文字母，阿拉伯数字，下划线(_)并且长度不能超过16位";
	}else{
		return true;
	}
	alert(errMessage);
	elem.focus();
	return false;
}

function ValidateLengthLimitedElement(elem,length,content){
	var value=elem.value,errMessage;
	if(value.length==0){
		errMessage=content+"不能为空";
	}else if(value.length>length){
		errMessage=content+"长度不能大于"+length+"个字符";
	}else{
		return true;
	}
	alert(errMessage);
	elem.focus();
	return false;
}

function ValidateMessageElement(elem){
	return ValidateLengthLimitedElement(elem,1000,"留言内容");
}

function ValidateCommentElement(elem){
	var value=elem.value,errMessage;
	if(value.length==0){
		errMessage="内容不能为空";
	}else if(value.length>2000){
		errMessage="内容长度不能大于2000个字符";
	}else{
		return true;
	}
	alert(errMessage);
	elem.focus();
	return false;
}

function ValidateKeywordElement(elem){
	var value=elem.value,errMessage;
	if(value.length==0){
		errMessage="关键词不能为空";
	}else if(value.length>30){
		errMessage="关键词长度不能大于30个字符";
	}else{
		return true;
	}
	alert(errMessage);
	elem.focus();
	return false;
}