onblur事件没有执行，请问怎么回事？

Question

  <script type="text/javascript">
         var xhr;
         function createXMLHttpRequest1() {
             alert(">>>");
         }
        function createXMLHttpRequest() {
            if (window.ActiveXObject) {//如果是IE浏览器
                return new ActiveXObject("Microsoft.XMLHTTP");
            }
            else if (window.XMLHttpRequest) {//非IE浏览器
                return new XMLHttpRequest();
            }
        }

        function userExists(CarNum) {
            if (CarNum != "") {
                // 请求字符串
                var url = "TC_Registra.aspx?CarNum=" + CarNum;
                // 1. 创建XMLHttpRequest组件
                xhr = createXMLHttpRequest();
                // 2. 设置回调函数
                xhr.onreadystatechange = readyDo;
                // 3. 初始化XMLHttpRequest组件
                xhr.open("GET", url, true);
                // 4. 发送请求
                xhr.send(null);
            }
        }

        function readyDo() {
            if (xhr.readyState == 4
                 && xhr.status == 200) {
                var b = xhr.responseText;
                if (b == "true") {
                    document.getElementById("mess_double").style.display = "inline";
                }
                else {
                    document.getElementById("mess_double").style.display = "none";
                }
            }
        }

    </script>
<form id="form1" runat="server" defaultbutton="btnAdd">
        <asp:ScriptManager ID="smDetail" runat="server" EnablePartialRendering="true">
        </asp:ScriptManager>
        <div class="maincontent">
            <asp:UpdatePanel ID="uplDetail" runat="server">
                <ContentTemplate>
                    <div class="panel">
                        <div class="title">明细</div>
                        <div class="content">
                            <table width="100%" border="0" cellpadding="0" cellspacing="0" class="smartGrid2">
                                <tr>


                                    <th width="13%" align="left">车牌号:</th>
                                    <td width="37%">
                                        <asp:TextBox ID="txtCarNum" runat="server" MaxLength="15"  onblur="createXMLHttpRequest1"/>
                                        <asp:RequiredFieldValidator runat="server" ID="BridgeCode_Null_Check" ControlToValidate="txtCarNum" ErrorMessage="“车牌号”不能为空" Display="None" Height="5px" Width="5px"  />
                                        <span class="RequiredWarningStyle" runat="server" id="spCarNum">*</span>
                                        <span id="mess_double"  style="display: none; color: Red">该车牌号已存在，请重新输入</span>

                                    </td>

                                                                    onblur事件没有执行，请问怎么回事？ 

Answer 1

没见你在哪里有onblur事件啊。。你用cs动态加的？状态转换函数最好改成下面的，要不出错了你都不知道什么问题。。

     function userExists(CarNum) {
          if (CarNum != "") {
              // 请求字符串
              var url = "TC_Registra.aspx?CarNum=" + CarNum+'&_dc='+new Date().getTime();//加时间戳防止IE下的缓存
              // 1. 创建XMLHttpRequest组件
              xhr = createXMLHttpRequest();
              // 2. 设置回调函数
              xhr.onreadystatechange = readyDo;
              // 3. 初始化XMLHttpRequest组件
              xhr.open("GET", url, true);
              // 4. 发送请求
              xhr.send(null);
          }
      }

      function readyDo() {
          if (xhr.readyState == 4) {
              if (xhr.status == 200) {
                  var b = xhr.responseText;
                  if (b == "true") {
                      document.getElementById("mess_double").style.display = "inline";
                  }
                  else {
                      document.getElementById("mess_double").style.display = "none";
                  }
              } else alert('动态页有问题！\n'+xhr.responseText);
          }
      }