Best way to restrict a text field to numbers only?

Question

I\'m using the following Javascript to restrict a text field on my website to only accept numerical input, and no other letters or characters. The problem is, it REALLY reje

Answer 1

This is a variation on Robert's answer that allows a single decimal point to be entered. If a decimal point has already been entered, only numbers are accepted as input.

JSFiddle - decimal number input

// Allow only decimal number input

$('#decimalInput').keypress(function (e) {
    var a = [];
    var k = e.which;

    for (i = 48; i < 58; i++)
    a.push(i);

    // allow a max of 1 decimal point to be entered
    if (this.value.indexOf(".") === -1) {
        a.push(46);
    }

    if (!(a.indexOf(k) >= 0)) e.preventDefault();

    $('span').text('KeyCode: ' + k);
});