well, you might be able to actually overwrite the the form's submit() function to call the onsubmit event...
something like this:
function MakeFormSubmitRaiseOnSubmit() {
for( var i = 0; i < document.forms.length; i++ ) {
var theForm = document.forms[i];
theForm.originalSubmit = theForm.submit;
theForm.submit = function() {
if ( this.onsubmit ) {
if ( this.onsubmit() != false ) {
this.originalSubmit();
}
} else {
this.originalSubmit();
}
};
}
}
this is just off the top of my head. I have no idea if it will work or what problems it may cause. Use at your own risk.