Javascript Runtime error
<p>why i am getting runtime error in javascript at </p>

<blockquote>
  <p>var ClientID = document.getElementById("ClientIDTextBox").value;</p>
</blockquote>

<p>and my code is:</p>

<pre><code>&lt;script type="text/javascript"&gt;
    var ClientID = document.getElementById("ClientIDTextBox").value;
    if (ClientID == "") {
        alert("Please enter ClientID")
      }
&lt;/script&gt;
</code></pre>

<p>please help me</p>
