<script type="text/javascript">
var r = confirm("Press a button");
if (r == true) {
<?php header('location:index.php');?>
}</script>
//Its redirect in index.php without conformation dialog and below code execute properly no any code contain simple navigation code..
<script type="text/javascript">
var r = confirm("Press a button");
if (r == true) {
x = "You pressed OK!";
}</script>