JQuery extension: numeric only input text

Here is the simply but re-usable approach, IMO: create an jquery numeric extension and then use the numeric extension in your input text box:

 
// numeric extension
jQuery.fn.onlyNumeric = function () {
    return this.each(function () {
        $(this).keydown(function (e) {
            var key = e.which || e.keyCode;
            if (!e.shiftKey && !e.altKey && !e.ctrlKey &&
                key >= 48 && key <= 57 || key >= 96 && key <= 105 ||
                key == 8 || key == 13 || key == 46 ||
                key == 35 || key == 36 || key == 37 || key == 39)
                return true;
            return false;
        });
    });
};
// use it in your input text box
$('#input_box').onlyNumeric();