在asp.net中这样的验证为什么不起作用呀?

   <script type="text/javascript">
   function check()
   {
   if(document.getElementById("TextBox1").value=="")
   {
   document.getElementById('TextBox1').focus();
   return false;
   }
    if(document.getElementById("TextBox2").value=="")
   {
   document.getElementById('TextBox2').focus();
   return false;
   }
   return true;
   }
   </script>
</head>
<body onload="document.getElementById('TextBox1').focus()" >
    <form id="form1" runat="server" onsubmit="return check()">

解决方案 »

  1.   

    用button的onclientClick="return check()";
    或
     <input type="submit" name="Submit1" value="提交" />
      

  2.   

    没反应？难道没有focus吗
    你搞个alert试试，代码应该没有问题
      

  3.   

    代码是没错，可TextBox控件从服务器返回给客户端后ID就不是你之前所命名的TextBox1了，你右击网页查看下源代码，看是否有TextBox1这个ID的输入框。
      

  4.   

       <script type="text/javascript">
       function check()
       {
       if(document.getElementById("TextBox1").value=="")
       {
       document.getElementById('TextBox1').focus();
       return false;
       }
        if(document.getElementById("TextBox2").value=="")
       {
       document.getElementById('TextBox2').focus();
       return false;
       }
       //return true;
       }
       </script>
    </head>
    <body onload="document.getElementById('TextBox1').focus()" >
        <form id="form1" runat="server" onsubmit="return check()">
        <div class ="div1" >
            <div class ="head" >
            </div>
            <div class ="cnt" >
                <div class ="div11" >
                    <div class ="div2" >
                    </div>
                    <div class ="div3" >
                        <div class ="div4"  >
                            <table style ="margin-top :30px;">
                                <tr>
                                    <td class ="td1" >
                                        学 号:</td>
                                    <td  class ="td2" >
                                        <asp:TextBox ID="TextBox1" runat="server"  CssClass ="textBox"></asp:TextBox></td>
                                </tr>
                                <tr>
                                    <td class ="td1" >
                                        密 码:</td>
                                    <td class ="td2">
                                        <asp:TextBox ID="TextBox2" TextMode="password" runat="server" CssClass ="textBox"></asp:TextBox></td>
                                </tr>
                                <tr>
                                    <td class ="td1">
                                        角 色:</td>
                                    <td class ="td2">
                                        <asp:DropDownList ID="DropDownList1" runat="server" CssClass ="dropDown">
                                        </asp:DropDownList></td>
                                </tr>
                                <tr>
                                    <td  class ="td3"  colspan="2">
                                        <asp:ImageButton ID="ImageButton1"  runat="server" ImageUrl="~/Images/loginbtn.jpg" OnClick="ImageButton1_Click" />
                                        &nbsp; &nbsp;&nbsp; &nbsp;<asp:ImageButton ID="ImageButton2" runat="server" ImageUrl="~/Images/resetbtn.jpg" /></td>
                                </tr>
                            </table>
                            </div>
                    </div>
                    <div class ="div5" >
                    </div>
                   
                   
                </div>
            </div>
        
        </div>
        </form>
    </body>
    </html>
    确实是没有反应.怪了!!!!!
      

  5.   


      <script type="text/javascript">
       function check()
       {
       if(document.getElementById("TextBox1").value=="")
       {
       document.getElementById('TextBox1').focus();
       return false;
       }
        if(document.getElementById("TextBox2").value=="")
       {
       document.getElementById('TextBox2').focus();
       return false;
       }
       //return true;
       }
       </script>
    </head>
    <body onload="document.getElementById('TextBox1').focus()" >
        <form name="form1" method="post" action="login.aspx" id="form1" onsubmit="return check()">
    <div>
    <input type="hidden" name="__VIEWSTATE" id="__VIEWSTATE" value="/wEPDwUJODAyNjM1NzkwD2QWAgIDD2QWAgIFDxAPFgYeDkRhdGFWYWx1ZUZpZWxkBQdyb2xlX2lkHg1EYXRhVGV4dEZpZWxkBQlyb2xlX25hbWUeC18hRGF0YUJvdW5kZ2QQFQQG5a2m55SfBuaVmeW4iA/ogIPor5XnrqHnkIblkZgM5oC7566h55CG5ZGYFQQKMDkwNzEyNDU2NgowOTA3MTI0NTY1CjA5MDcxMjQ1NjQKMDkwNzEyNDU2MxQrAwRnZ2dnZGQYAQUeX19Db250cm9sc1JlcXVpcmVQb3N0QmFja0tleV9fFgIFDEltYWdlQnV0dG9uMQUMSW1hZ2VCdXR0b24yH7dVDk5NGHZjPOcRGOlPvFZynCw=" />
    </div>    <div class ="div1" >
            <div class ="head" >
            </div>
            <div class ="cnt" >
                <div class ="div11" >
                    <div class ="div2" >
                    </div>
                    <div class ="div3" >
                        <div class ="div4"  >
                            <table style ="margin-top :30px;">
                                <tr>
                                    <td class ="td1" >
                                        学 号:</td>
                                    <td  class ="td2" >
                                        <input name="TextBox1" type="text" id="TextBox1" class="textBox" /></td>
                                </tr>
                                <tr>
                                    <td class ="td1" >
                                        密 码:</td>
                                    <td class ="td2">
                                        <input name="TextBox2" type="password" id="TextBox2" class="textBox" /></td>
                                </tr>
                                <tr>
                                    <td class ="td1">
                                        角 色:</td>
                                    <td class ="td2">
                                        <select name="DropDownList1" id="DropDownList1" class="dropDown">
    <option value="0907124566">学生</option>
    <option value="0907124565">教师</option>
    <option value="0907124564">考试管理员</option>
    <option value="0907124563">总管理员</option></select></td>
                                </tr>
                                <tr>
                                    <td  class ="td3"  colspan="2">
                                        <input type="image" name="ImageButton1" id="ImageButton1" src="Images/loginbtn.jpg" style="border-width:0px;" />
                                        &nbsp; &nbsp;&nbsp; &nbsp;<input type="image" name="ImageButton2" id="ImageButton2" src="Images/resetbtn.jpg" style="border-width:0px;" /></td>
                                </tr>
                            </table>
                            </div>
                    </div>
                    <div class ="div5" >
                    </div>
                   
                   
                </div>
            </div>
        
        </div>
        
    <div> <input type="hidden" name="__EVENTVALIDATION" id="__EVENTVALIDATION" value="/wEWCQKoxNnUBwLs0bLrBgLs0fbZDALhh5jtCALhh5ztCALhh4DtCALhh6TtCALSwpnTCALSwtXkAoIKhs7ZkwH9Tg9PMNfzV/t8gKVd" />
    </div></form>
    </body>
    </html>页面源文件
      

  6.   

    需要修改如下几个地方：
     
       <script type="text/javascript"> 
      function check() 
      { 
      if(document.getElementById("<%=TextBox1.ClientID %>").value=="") 
      { 
      document.getElementById("<%=TextBox1.ClientID %>").focus(); 
      return false; 
      } 
        if(document.getElementById("<%=TextBox2.ClientID %>").value=="") 
      { 
      document.getElementById("<%=TextBox2.ClientID %>").focus(); 
      return false; 
      } 
      } 
      </script> <body onload="document.getElementById('<%=TextBox1.ClientID %>').focus()" >  <asp:ImageButton ID="ImageButton1"  runat="server" ImageUrl="~/Images/loginbtn.jpg" OnClientClick="return check()"  />