To do exactly what you say you want to do, code like this should work.
<cfform action="abc.cfm"
method="post"
onsubmit="return someJSFunction(this)">
The function, someJSFunction() will run after your form validates. However, you might be doing things the hard way. Instead of doing ajax requests to submit data, it would probably be a lot easier to submit that data with ColdFusion code in the form action page, abc.cfm in this example.