The method given below may not sometimes work.
The following method has always worked with me:
just put the following 3 lines in your PHP code
$sec is the time in second after which the browser would automatically go to the url. Set it to 0 if you do not want to give any time.
You can use this function on the events of various html/form objects (eg.-onclick for button).eg.
<input type=button value="Go to Php.net" onclick=setTimeout("location.href='php.net'",0)>
Use this to one step back
<input type="button" value="Back" onclick=history.go(-1)>