I want to replace string like this
<blockquote>
  <p><strong>Possible Duplicate:</strong><br>
  <a href="http://stackoverflow.com/questions/2236235/how-to-replace-a-string-at-a-particular-position">How to replace a string at a particular position</a>  </p>
</blockquote>



<p>I have string</p>

<pre><code>val ="Bhavik Patel. hi Bhavik Patel.Bhavik Patel posted Question "
start=17;
end=28;
</code></pre>

<p>I want to replace string start from 17 to end at 28th character.</p>
