onlyDigits.js

function FormatNumber(val) {
    var split = val.split('.');
    if (split.length > 1) return OnlyNumbersAllowed(split[0]) + '.' + OnlyNumbersAllowed(split[1]);
    else return OnlyNumbersAllowed(split[0]);
}

function OnlyNumbersAllowed(val) {
    return val.replace(/\D/g, '');
}



(function ($) {
    "use strict";
        $('#edit-user-invest').keyup(function (e) {
            $(this).val(FormatNumber($(this).val()));
        });
})(jQuery);