找不到asp:textbox in Javascript语言

您的代码正在尝试在客户端脚本中添加事件处理程序属性。这需要在服务器端代码块中发生。比如:

<script runat="server"> 
    UserName.Attributes.Add("onKeyDown", "KeyDownHandler('" + btn.ClientID + "')"); 
    Password.Attributes.Add("onKeyDown", "KeyDownHandler('" + btn.ClientID + "')"); 
</script>
<script type="text/javascript">
function KeyDownHandler(btn) 
{ 
    if (event.keyCode == 13) 
    { 
        event.returnValue=false;     
        event.cancel = true; 
        document.getElementById(btn).click(); 
    } 
} 
</script> 

在aspx文件中,添加将现有用户名和密码文本框绑定到名为KeyDownHandler的客户端事件处理程序的服务器脚本:

<script runat="server">
   protected void Page_Load(object sender, EventArgs e)
   {
      TextBox userNameControl = FindControl("UserName") as TextBox;
      TextBox passwordControl = FindControl("Password") as TextBox;

      if (userNameControl != null)
         userNameControl.Attributes.Add("onKeyDown", "KeyDownHandler(this)"); 

      if (passwordControl != null)
         passwordControl.Attributes.Add("onKeyDown", "KeyDownHandler(this)"); 
   }
</script>

然后声明事件处理程序的客户端脚本:

<script type="text/javascript">
function KeyDownHandler(domButton) 
{ 
    if (event.keyCode == 13) 
    { 
        event.returnValue=false;     
        event.cancel = true; 
        domButton.click(); 
    } 
} 
</script>

尝试按以下方式连接事件处理程序参数:

<script type="text/javascript">
    window.onload = function() {
    UserName.Attributes.Add("onKeyDown", "KeyDownHandler(this)");
    Password.Attributes.Add("onKeyDown", "KeyDownHandler(this)");
}

function KeyDownHandler(domButton)
{
    if (event.keyCode == 13)
    {
        event.returnValue=false;    
        event.cancel = true;
        domButton.click();
    }
}
</script>