gistfile1.js

$.fn.validatesNumericality = function(options) {
    return this.each(function() {
        var el = $(this);
        // TODO: I18n
	 	var thousandsSep = ',';
	    var decimalSep = '.';

        var settings = $.extend({
                            invalidClass: 'invalid-numericality',
                            onlyInteger: false,
                            validatesOn: ['change', 'blur'],
                            when: function() {return true;}
                        }, options);

        el.bind(settings.validatesOn.join(' '), function() {
            if (settings.when(el)) {
				var val = el.val().replace(new RegExp("/"+thousandsSep+"/", 'g'), '');
				if (decimalSep !== '.') {
					val = val.replace(RegExp("/"+decimalSep+"/"), '.');
				}
                if (isNaN(val)) {
                    el.trigger('invalid')
                        .trigger('invalid-numericality')
                        .closest('fieldset')
                        .addClass(settings.invalidClass);
                } else {
                    el.trigger('valid')
                        .trigger('valid-numericality')
                        .closest('fieldset')
                        .removeClass(settings.invalidClass);
                }
            }
        });
    });
};