jquery numeric for decimals

HTML

<input class="numeric" type="text" />

JavaScript

/*
 *
 * Copyright (c) 2006-2011 Sam Collett (http://www.texotela.co.uk)
 * Dual licensed under the MIT (http://www.opensource.org/licenses/mit-license.php)
 * and GPL (http://www.opensource.org/licenses/gpl-license.php) licenses.
 * 
 * Version 1.3.1
 * Demo: http://www.texotela.co.uk/code/jquery/numeric/
 *
 */
(function($) {
/*
 * Allows only valid characters to be entered into input boxes.
 * Note: fixes value when pasting via Ctrl+V, but not when using the mouse to paste
  *      side-effect: Ctrl+A does not work, though you can still use the mouse to select (or double-click to select all)
 *
 * @name     numeric
 * @param    config      { decimal : "." , negative : true }
 * @param    callback     A function that runs if the number is not valid (fires onblur)
 * @author   Sam Collett (http://www.texotela.co.uk)
 * @example  $(".numeric").numeric();
 * @example  $(".numeric").numeric(","); // use , as separator
 * @example  $(".numeric").numeric({ decimal : "," }); // use , as separator
 * @example  $(".numeric").numeric({ negative : false }); // do not allow negative values
 * @example  $(".numeric").numeric(null, callback); // use default values, pass on the 'callback' function
 * @example  $(".numeric").numeric({ scale: 2 }); // allow only two numbers after the decimal point.
 * @example  $(".numeric").numeric({ scale: 0 }); // Same as $(".numeric").numeric({ decimal : false });
 * @example  $(".numeric").numeric({ precision: 2 }); // allow only two numbers.
 * @example  $(".numeric").numeric({ precision: 4, scale: 2 }); // allow four numbers with two decimals. (99.99)
 *
 */
$.fn.numeric = function(config, callback)
{
	if(typeof config === 'boolean')
	{
		config = { decimal: config };
	}
	config = config || {};
	// if config.negative undefined, set to true (default is to allow negative numbers)
	if(typeof config.negative == "undefined") { config.negative = true; }
	// set decimal point
	var decimal = (config.decimal === false) ? "" : config.decimal ||...