Alert if variable contains non numeric characters?

Question

'p' can only store "$", commas, dots or numbers.

How can I show an alert if it contains any other character?

Answer 1

if (p.match(/[^$,.\d]/))
    alert('error!');

Live DEMO

You can use this Excellent regex cheat sheet.

Answer 2

Consider:

if (/[^$,\.\d]/.test(p)) {
  // value has characters other than $ , . 0-9.
};

The regular expression test method returns a boolean value, whereas match returns an array and so is dependent on type conversion when used in a simlar manner.