F12 opens and closes your browser console, in the log tab, you will see any errors found, that will help you look at what the error is.
It can be anything from a typo to using wordpad.
You should be using a plain text editor like notepad or notepad++ or something that will save plain text files. Wordprocessors and wordpad and many of the notepads out there do not produce plain text output.
So errors can be part of the editor you use, " are not seen the same, in some editors, its a different ASCII value than the " that computers know and understand.
You may find the error yourself..! You never know...