The currant page submit trigger relies on the forms method being set to post.
your form:
<form action="" method="get">
is set to use the get method, change it to use the post method instead:
<form action="" method="post">
you also have a goToURL() function applied to the forms submit button:
<input name="Submit" type="submit" style="font-size:10px" onclick="goToURL()" value="Make Payment"/>
you should remove the onclick event:
<input name="Submit" type="submit" style="font-size:10px" value="Make Payment"/>
