Google Script for Uploading File Not Working - file-upload

Question

I wrote a script for uploading files to my Google Drive using the Google Script. I deployed it as a WebApp but it's not working and I don't know why. The button just gets stuck on "Subiendo..." and never changes anything inside my Drive. I'm sure I gave the script all the permissions and I already tried to see what's happening on my own without any sucess. Can you maybe help me find what should I do? I post the code here:
Code.gs
function doGet() {
return HtmlService.createHtmlOutputFromFile('main').setSandboxMode(HtmlService.SandboxMode.IFRAME);
}
function serverFunc(theForm) {
try{
var folder_name = "publicaciones";
var folder,folders = DriveApp.getFoldersByName(folder_name);
if(folders.hasNext()){
folder = folders.next();
}else{
folder = DriveApp.createFolder(folder_name);
}
Logger.log("TheForm", theForm == null);
var blob = theForm.theFile;
Logger.log("Blob!", blob == null);
var file = folder.createFile(blob);
Logger.log("File:", file.getName());
return "Archivo subido exitosamente: " + file.getUrl();
} catch(error){
Logger.log("error: ", error.toString());
return error.toString();
}
}
** main.html **
<div>
<form id="myForm">
<input type="file" name="theFile">
<input type="hidden" name="anExample">
<br>
<input type="button" value="Subir Archivo" onclick="this.value='Subiendo...';
google.script.run.withSuccessHandler(fileUploaded).serverFunc(this.parentNode);
return false;">
</form>
</div>
<div id="output">
</div>
<script>
function fileUploaded(status) {
document.getElementById('myForm').style.display = 'none';
document.getElementById('output').innerHTML = status;
}
</script>
I'd appreaciate any help or pointers you can give me. Thanks a lot!

Answer 1

Looks like there is a bug currently that Google is working on. I found a possible fix:
Change your input tag to this:
<input type="button" value="Subir Archivo" onclick="callServerCode()"/>
Add a function to the <script> tag:
<script>
function callServerCode() {
var formToSend = document.getElementById('myForm');
google.script.run
.withSuccessHandler(fileUploaded)
.serverFunc(formToSend);
};
function fileUploaded(status) {
document.getElementById('myForm').style.display = 'none';
document.getElementById('output').innerHTML = status;
}
</script>
Note that inside the new function, it gets the form using var formToSend = document.getElementById('myForm');
And change IFRAME to NATIVE.

Answer 2

It's a doc issue needs to fix with Google when using SandBoxMode=IFRAME currently. See here. I've tested it works by swapping IFRAME to NATIVE. You can simply do it:
function doGet() {
return HtmlService.createHtmlOutputFromFile('main');
}

Answer 3

Google has turned of NATIVE for SandBoxMode. It is now set to IFRAME only.
See here