[jQuery] Validator plugin class="cancel" not working when submit called from script

When the user clicks on an input button where "cancel" is added to the
class attribute, the form submits as expected, but when the the input
button is submitted by script like this, $("input
[name='Btn_Cancel']").submit(), then the validation fires as if the
class="cancel" is not there.

Any idea why the difference in the ways of submitting the form?

I'm using jquery 1.3.2 and jquery.validate 1.6.

Thanks