Javascript function need allow numbers, dot and comma

Question

I need to create a function to allow numbers dot and comma. So anyone corrects the following function

function on(evt) {
  var theEvent = evt || window.event;
  var key = theEvent.keyCode || theEvent.which;
  key = String.fromCharCode( key );
  var regex = /[0-9]|\./;
  if( !regex.test(key) ) {
    theEvent.returnValue = false;
    if(theEvent.preventDefault) theEvent.preventDefault();
  }
}

Answer 1

Firstly your regex currently doesn't allow comma, which is your requirement.

Secondly, you haven't used any quantifier, so your regex will match only a single character - one of [0-9] or a dot. You need to use a quantifier.

Thirdly, instead of using pipe, you can move all characters inside the character class only.

Try using the below regex:

/^[0-9.,]+$/

Quantifier + is used to match 1 or more occurrence of the pattern.
^ and $ anchors match the beginning, and end of the string respectively.

Answer 2

No need for JavaScript:

<input type="text" pattern="[0-9.,]+" title="Please enter a valid decimal number." />

Modern browsers will handle this perfectly.

If you want to specifically allow commas as thousand separators and a single decimal point, try this:

... pattern="\d{1,2}(,\d{3})*(\.\d+)?" ...

Note that I am firmly against blocking user input. They should be able to type what they want, and then told if they enter something invalid.

Answer 3

Your regex is incorrect.

var regex = /^[0-9.,]+$/;

Regex javascript, why dot and comma are matching for \

https://stackoverflow.com/tags/regex/info