Best way to locate source of Warning: Empty string passed to getElementById()

Question

Warning: Empty string passed to getElementById().
Source File: chrome://browser/content/browser.xul
Line: 0

Some days ago I star

Answer 1

In my case this was caused by Firefox performing HTML5 checks on the input fields on my form. Once the "required" property was removed from the form elements everything seemed to work fine again.

This was something brought about by the MVC framework I use which generates these properties based on the model validation rules that require a field to be non-empty.