How does server tags work in javascript?
<p>I have written a code</p>

<pre><code>function validate()
 {
 if(document.getElementById("&lt;%=txtSearch.ClientID %&gt;").value=="")
 {
  message="Enter the User Id To Search";
  document.getElementById("&lt;%=lblMessage.ClientID %&gt;").innerHTML=message;
  return false;
 }
</code></pre>

<p>Here I am using <code>&lt;%= %&gt;</code> tags. I want to know how do they work without making a trip to the server?</p>
