登录按钮不能用

我在后台写了一个方法,用作登录,方法如下

private void regScript()
    {
        StringBuilder script = new StringBuilder(300);
        script.Append("<script type='text/javascript'>");
        script.Append("function userLogin(){");
        script.Append("var _userName=document.getElementById('" + iptName.ClientID + "').value;");
        script.Append("var _password=document.getElementById('" + iptPWD.ClientID + "').value;");
        script.Append("var _test=login.userLogin(_userName+','+_password).value;");
        script.Append("if(_test!='sccuess'){");
        script.Append("alert('密码或用户名错误！');");
        script.Append("var _pnlLogin=document.getElementById('" + pnlLogin.ClientID + "');");
        script.Append("_pnlLogin.style.display='';");
        script.Append("var _pnlLogout=document.getElementById('" + pnlLogout.ClientID + "');");
        script.Append("_pnlLogout.style.display='none';}");
        script.Append("else{var _pnlLogin=document.getElementById('" + pnlLogin.ClientID + "');");
        script.Append("_pnlLogin.style.display='none';");
        script.Append("var _pnlLogout=document.getElementById('" + pnlLogout.ClientID + "');");
        script.Append("_pnlLogout.style.display='';");
        script.Append("document.getElementById('" + lblName.ClientID + "').innerText=_userName;}");
        script.Append("}");
        script.Append("function userLogout(){");
        script.Append("login.userOut();");
        script.Append("document.getElementById('" + pnlLogin.ClientID + "').style.display='';");
        script.Append("document.getElementById('" + pnlLogout.ClientID + "').style.display='none';");
        script.Append("document.getElementById('" + iptName.ClientID + "').value='';");
        script.Append("document.getElementById('" + iptPWD.ClientID + "').value='';}");
        script.Append("</script>");
        if (!this.Page.IsClientScriptBlockRegistered("client"))
        {
            this.Page.RegisterClientScriptBlock("client", script.ToString());
        }
    }

在初始时绑定:
protected void Page_Load(object sender, EventArgs e)
    {
        try
        {//用户已经登录
            userName = this.Session["userName"].ToString().Trim();
            this.pnlLogin.Style.Add("display", "none");
            this.pnlLogout.Style.Add("display", "");
            this.lblName.Text = Session["userName"].ToString();
        }
        catch { }
        Ajax.Utility.RegisterTypeForAjax(typeof(Controls_login));
        regScript();

    }

前台调用:<INPUT type="button" value="登 录" onclick="javascript:userLogin();">

可是这个登录按钮不管用,哪位大侠看出是哪里错了??