Form problems, not submitting right!

Has any one ever had the problem of when filling out a form then hitting enter it doesnt post? I’m making a search thing that has a method=“post” and action=“search.php” but when you hit enter, it just goes to search without actually displaying any data, where if i were to click the submit button with my mouse, it posts the data.

Odd?

Thanks

OH, and example: www.omniboggle.com try using enter to submit a term and if it doesnt work, go back and click the submit button.