History & the back button

Hi there, I realise that this isn't strictly to do with PHP but maybe PHP could provide me with a workaround... I've got a site where tables of data (customer names etc) are automatically generated from MySQL using PHP and displayed along with hyperlinks which reference an operation like "delete" or "add" or "update". (In fact I copied the idea from Ying Zang's article about building an on-line market store called mymarket on PHPBuilder.com) So my links look something like this: <a href="http://full-url?mode=del&name=customer">Customer</a> Now to my question. How do I stop a "back button" from re-using this link after it has been done once already? I have tried the javascript: [onclick window.location.replace="different url"] but when I do this, it actually changes the url before it is sent back to PHP so the action never happens! Am I just being thick? I can write routines to test for repetition but this seems like a lot of effort which is likely to introduce more bugs than it fixes... Or should I drop this method altogether and use forms and buttons instead? Any insights would be extremely welcome! Alan Lord Trainee PHP programmer ;-) ________________________________________________________________________ Get Your Private, Free E-mail from MSN Hotmail at http://www.hotmail.com