function checkCode()
{
    var bool = 1;
    var code =document.getElementById("textfield4").value;
    if(code=="")
    {
       bool = 0;
       document.getElementById("okcode").style.display="block";
       
    }
    else
    {
        var ReturnValue=$.ajax({
                                url: AjaxAreaCheck.aspx?code1="+code,
                                async: false
                                }).responseText;
       //运行到这里就提示 这个错误 排查无果 求各位大侠指点 感激不尽
 if(ReturnValue=="0")
        {
            bool = 1;
            document.getElementById("okcode").style.display="none";        }
        else
        {
            bool = 0;
            document.getElementById("okcode").style.display="block";
   
        }
    }
    return bool; 
}