Getting Error “Form submission canceled because the form is not connected”

I have an old website with JQuery 1.7 which works correctly till two days ago. Suddenly some of my buttons do not work anymore and, after clicking on them, I get this warning in the console:

Form submission canceled because the form is not connected

The code behind the click is something like this:

 this.handleExcelExporter = function(href, cols) {
   var form = $('<form method="post"><input type="submit" /><input type="hidden" name="layout" /></form>').attr('action', href);
   $('input[name="layout"]', form).val(JSON.stringify(cols));
   $('input[type="submit"]', form).click();
 }

It seems that Chrome 56 doesn’t support this kind of code anymore. Isn’t it? If yes my question is:

1. Why did this happened suddenly? Without any deprecation warning?
2. What is the workaround for this code?
3. Is there a way to force chrome (or other browsers) to work like before without changing any code?

P.S. It doesn’t work in the latest firefox version either (without any message). Also it does not work in IE 11.0 & Edge! (both without any message)

Answer

Quick answer : append the form to the body.

document.body.appendChild(form);

Or, if you’re using jQuery as above

$(document.body).append(form);

Details : According to the HTML standards, if the form is not associated to the browsing context(document), the form submission will be aborted.

HTML SPEC see 4.10.21.3.2

In Chrome 56, this spec was applied.

Chrome code diff see @@ -347,9 +347,16 @@

P.S about your question #1. In my opinion, unlike ajax, form submission causes instant page move.
So, showing ‘deprecated warning message’ is almost impossible.
I also think it’s unacceptable that this serious change is not included in the feature change list. Chrome 56 features – www.chromestatus.com/features#milestone%3D56