The existing form in sharepoint page is in the way

Hi,

I am trying to deploy my own web form. It has some JS validation and submit.

The current form on the page:

<formname="aspnetForm" method="post" action="WPPrevw.aspx?ID=79" onsubmit="javascript:return WebForm_OnSubmit();" id="aspnetForm">
is interceptuing my validation javascript. How can I remove that 
onsubmit="javascript:return WebForm_OnSubmit();" from the form tag, or better yet, can this form tag be remobved alltogether?
Thanks.