title: How to Validate textbox so that I cannot enter zero as first digit?
body: <p>How should I validate my textbox so that I the text entered shouldnt start with zero. I can enter zero anywhere else in the textbox...</p>
  
  <pre><code> function checkFirst() {
      var text = document.getElementById('&lt;%=textbox.ClientID %&gt;').value.charAt(0);
      if (text == "0") {
          return false;
      }
  }
  </code></pre>
  
  <p>I tried with this code but it shows JavaScript Runtime error is thrown. I dont know how to clear it.</p>
  
  <p>If there are any choices in regular expressions too pls suggest me some. </p>