In PHP I want to use a script held in a separate file to process a form and validate it. If there are errors I want the form to display the errors and original values for the user to change.
At the moment the validation script is on the same page as the form and all works ok. However I would like this away from the form and send the form variables to the script using the 'action' in the form.
If I do this though, how can I then go back to the form with error messages and original values — do I simply use $\_POST in the script and a header location? or is there a better method.
If the form validates okay I'll then go to a separate page (using a header).

Can anyone help me understand the process/logic I should be trying to achieve and the function s to past variables between the pages ($\_GET?)