The only thing I can see that might make a difference is that the target is an "https://" and not an "http"
I'm using a picture as the submit button.
In the <img is an onclick='submitit()'
The form in the html looks like this...
<form name='theform' id='theform' action='https://www.thetarget.com/whatever' method='GET' target='_self'>
<!-- some fields -->
The submitit() function looks like this...
//do some stuff here to validate
//alert the validation result... shows the alert so there's nothing in the function to that point preventing it from working.
I can't see any reason why that doesn't work.
Note that I've also tried
theform.submit(), but that doesn't work either.
However, if I put a submit button on the form and click that instead, it works.