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

Was receiving this warning in Firefox.

I just came across this warning and found that there were labels for input fields but the labels for attribute was not set/empty so just completing the for attribute fixed this issue for me.

// Label's for attribute not set which caused the warning in FF

e.g. Text