title: Only allow Numbers in input Tag without Javascript
body: <p>I am fairly new. I am creating a webpage that ask a user for their ID. I want it to be a required field and only allow numbers.  I appreciate if you lead me in the correct direction. this is what I have so far.</p>
  
  <pre><code>&lt;%@ Page Language="C#" Inherits="System.Web.Mvc.ViewPage&lt;dynamic&gt;" %&gt;
  
  &lt;!DOCTYPE html&gt;
  
  &lt;html&gt;
  &lt;head runat="server"&gt;
    &lt;title&gt;Search&lt;/title&gt;
  &lt;/head&gt;
  &lt;body&gt;
   &lt;div&gt;
    &lt;table align="center"&gt;
      &lt;tr&gt;
          &lt;td class="label"&gt;
              Enter ID:
          &lt;/td&gt;
           &lt;td&gt;
              &lt;input type="text" name="UserId" id="UserId" /&gt;
          &lt;/td&gt;
       &lt;/tr&gt;
     &lt;/table&gt;
    &lt;/div&gt;
   &lt;/body&gt;
  &lt;/html&gt;
  </code></pre>