At what point does the upload occur in an html form? - html

Question

Okay, so I've been handed this code (surrounding code is standard head/body framework and script defining "ConvertPPT2HTML()"):
<h1>Powerpoint Upload</h1>
<form id="form2" enctype="multipart/form-data" action="test_ppt_uploader.php" method="POST">
<table border="0" >
<tr>
<td ><b>Select File:</b> </td>
<td>
<input type=hidden name="pptfilename" id="pptfilename" value="">
<input type=hidden name="tempfilename" id="tempfilename" value="">
<input type="file" name="uploadedfile" id=upload size=25 >
</td>
<td>
<input type="submit" name=sub value="Upload File" onclick=" return ConvertPPT2HTML();"></td>
</tr>
</table>
</div>
</form>
The requirements are to:
Stop it from uploading any files from the client to the server
Keep it doing the ConvertPPT2HTML work (basically using AJAX to open the actual ppt file at the supplied path, saving a temp copy and a copy as html and then zipping it up for later upload)
The actual file is available in the php script after submit is hit, so my initial take was to remove:
enctype="multipart/form-data" action="test_ppt_uploader.php" method="POST">
Which does the job. But I'm not sure if the file is still being uploaded and discarded, or if it's not being uploaded at all.
I do want to keep the file widget around for browsing the file system, I just want to ensure it merely gives you a path, not an uploaded file.
So the specific question is Does the code below still upload anything?
<h1>Powerpoint Converter</h1>
<form id="form2">
<table border="0" >
<tr>
<td ><b>Select File TWJC:</b> </td>
<td>
<input type="file" name="uploadedfile" id=upload size=25 >
</td>
<td>
<input type="submit" name=sub value="Upload File" onclick=" return ConvertPPT2HTML();">
</td>
</tr>
</table>
</div>
</form>

Answer 1

Yes, if ConvertPPT2HTML() returns true then your form will still upload the PPT to the server. The form's action attribute defaults to the current URL.
You can use the "Network" tab in Chrome or IE's developer tools to watch the form submission.