//客户端验证函数
function requireField(o)
{
   var j_username = /^(\w){3,20}|[^u4e00-u9fa5]{2,20}$/;
   var j_password=/^(\w){4,20}$/;
  var j_captcha_response=/^(\w){3,6}$/;


 var j_username_error = "至少3位";
var j_password_error ="密码至少为4位";
var j_captcha_response_error ="验证码不能为空";
   if(o.value.match(eval(o.id)))
   {
      return true;
   }
   else
   {
      $('#'+o.id+'_img').html("<img src='image/yanzheng/exclamation.gif' />");
      $('#'+o.id+'_error').html(eval(o.id+'_error')).attr("style","color:red;");
   }
   return false;
}

//submit前的验证函数
function validate() {
    var biaozhi = true;
    $("input[needValidate='true']").each(function(i){
       if(!requireField(this))
       { biaozhi = false; }
       }
    )
    return biaozhi;
}