Need help form not sending properly JS

Hi all I need some help with a form
Basically I have a HTML form that allows attachments
However it also has a JS file attached to it with is causing me problems.
The JS is meant to process the form but
it wont process the form and send it if there is no attachment

The form is below. I have done the obvious things like change from false to true and back again
Removed the if statement and tried to put in an else but I have had no luck
As I said if there is a file attached it works fine but if not the send button s dead

Any ideas

function enableUpload() {
var uploadInput = document.getElementById('uploadInput');
if (uploadInput.value != ''){
//enables the submit button to upload the file
document.getElementById('submitButton').disabled = false;
//makes the file picker element invisible
document.getElementById('uploadDiv').style.display = 'none';
//shows the element which show the filename
document.getElementById('selectedFileDiv').style.display = '';
//removes span content and add the file name
var filenameSpan = document.getElementById('filename');
while( filenameSpan.firstChild ) {
filenameSpan.removeChild( filenameSpan.firstChild );
}
//adds the filename to the span
filenameSpan.appendChild( document.createTextNode(uploadInput.value) );
}
}
function selectNewFile() {
//shows the file picker element
document.getElementById('uploadDiv').style.display = '';
//makes the element which show the filename invisible
document.getElementById('selectedFileDiv').style.display = 'none';
//disable the submit button to upload the file
document.getElementById('submitButton').disabled = true;
//removes the file name in the input
document.getElementById('uploadInput').value = '';
}// JavaScript Document

Code (markup):

 

You didn't actually include the form it's trying to process -- but generally speaking it looks like you've gotten a bit too complex for your own good manipulating style values that should be handled with a class swap, functional code instead of event attachments, etc, etc...

Really though without seeing the markup being manipulated, the scripting is gibberish... scripting without seeing how the markup is calling it or how it's being attached to the markup; might as well be an alien language.