first off, sorry cross-posting between here and javascript section

The following code run fine, but it does not sleep 10 seconds. Just run the first and third lines immediately.
Code:
<?php

	echo "<script>var newWindow=window.open('testpage1.html', 'TestWindow 1', 'width=200,height=200');</script>";
	
	sleep(10);
	
	echo "<script>newWindow.close();</script>";

?>