How to prevent invalid characters from being typed into input fields

Question

Onkeydown, I run the following JavaScript:

function ThisOnKeyDown(el) {
   if (el.title == \'textonly\') {
       !(/^[A-Za-zÑñ-\\s]*$/i).test(e         


        

Answer 1

The above code does it says- allows ONLY numbers. You can modify it by adding exception to say BACKSPACE for example like this