Javascript Regex with numbers

Javascript Regex is a powerful tool. However, there is something you must take note when doing validation with numbers.

if your regex is /[0-9]+/ and your intention is to ensure that the input is just numbers. You would be surprised that when you enter ".1" or "1." it still passes.

I am not sure what happened but isNaN also behaves this way.

To ensure that only numbers is valid you would have to set the regex as /^[0-9]+$/