Is it mandatory to give a function or variable name as a captial or small letter together?

Question

"function leTTer() or function letter()" "var bOx = 1 or var box = 2 " which is better way and why?

Answer 1

it's all about readability. capital letter at the beginning for constants. camel lettering for function names like getValue(). underscores for variables like max_height. that's how I do it. it's easy to read and you see immediately what is what.

Answer 2

I got my answer. Thank you very much for your good explanation.