function onPost(form)
	{
		var	re	= new RegExp("[^\x20]+");
		if(re.test(form.nickname.value) == true && getStrLength(form.nickname.value) > 20)
		{
			alert("用户昵称最多为20字符！每个汉字相当于两个字符");
			form.nickname.focus();
			return false;
		}
		if(re.test(form.content.value) == false)
		{
			alert("请输入你的留言！");
			form.content.focus();
			return false;
		}
		//alert("len: " + getStrLength(form.content.value));
		if(getStrLength(form.content.value) > 2000)
		{
			alert("发言最多为2000字符！每个汉字相当于两个字符");
			form.content.focus();
			return false;
		}

		return true;
	}
	function getStrLength(str){
		var totallength=0;
		for (var i=0; i < str.length;i++){
			var intCode=str.charCodeAt(i);
			if (intCode>=0&&intCode<=128) {
				totallength=totallength+1;
			}else {
				totallength=totallength+2;
			}
		} 
		return totallength;	
	}	
	
	
$(document).ready(function(){
						   $('#nickname').focus(function(){
										var nickname = $(this).val();
										if(nickname == '请填写姓名'){
											$(this).val('');
											}
														 });
						   });