Multiple actions a single submit button

[Anon]

I'm using a PHP shopping cart system and want to be able prevent the user from clicking the submit button on the checkout page more than once.

I thought of having a Java floating box cover the button to prevent a second click but this would require two actions from the same button. 1 call for the floating box to display & 2 pass the info in the checkout page to the php program generate the order.

Any ideas on how this could be done?

[paulm]

two options;

call 2 javascript routines on one click i.e. <a href="#1" onclick="dofirst(); donext();">

or

set a variable in php when the submit button is clicked the first time and only run the checkout routine if the variable is not already set. ie.
if(!isset($checkedout))
do routine
else
don't do it