Question

This is my current code it removes all non-numeric characters except $, commas and dots from an input when as user types:

<input type="text" id="price" name="price" onkeyup="updatePrice(this.value)">

function updatePrice(p) {
    document.getElementById("price").value = p.replace(/[^0-9$.,]/g, '');
    }

The problem is that it removes characters after typing them so if you type A you see it for a fraction of a second before it disappears. Keydown is no good since it runs the script before the input actually changes.

How can I completely prevent these forbidden characters from appearing on the input?

Answer 1

• use onblur to perform validation when the input loses its focus – the user dosen’t have to be aware of this during typing.
• user dosen’t have to be aware of this at all – you can perform the validation upon submit.