BoldX error

[GiganticThirstyHerald]

Hello!
I've copy-pasted your BoldX scripts to my table and got this error:

TypeError: Cannot read property 'indexOf' of null
    at [unknown function](Code:37:51)
    at checkWords(Code:37:25)
    at main(Code:28:11)

[GiganticThirstyHerald]

And I've found what's going on.
If any cells in range are empty, it returns this error.
How to work around this?

Also, for some reason, it doesn't work with upper-case letters, even tho, regex match should match them.

[AlbertBaubleDeem]

The index.html is broken as the function runBoldX() cannot retrieve values of elements range and words. I am a beginner, so I don't know how to fix it. I just used Code.gs and hardcoded my needed values into the main() :)

function runBoldX() { var range = document.getElementById("range").value; var words = document.getElementById("words").value; google.script.run.main(range, words);