title: AVoid Postback on OnClick Event
body: <p>I have a <code>Javascript</code> function </p>
  
  <pre><code>show()
  {
  alert("hello");
  }
  </code></pre>
  
  <p>which runs on ASP Button OnClick Event.</p>
  
  <p>When I click the button of alert message box showing "hello", postback occurs. Is there any way I cant prevent this postback?</p>