/*
 *
 * Copyright (c) 2006/2007 Sam Collett (http://www.texotela.co.uk)
 * Licensed under the MIT License:
 * http://www.opensource.org/licenses/mit-license.php
 * 
 * Version 1.0
 * Demo: http://www.texotela.co.uk/code/jquery/numeric/
 *
 * $LastChangedDate: 2007-05-29 11:31:36 +0100 (Tue, 29 May 2007) $
 * $Rev: 2005 $
 */
 
/*
 * Allows only valid characters to be entered into input boxes.
 * Note: does not validate that the final text is a valid number
 * (that could be done by another script, or server-side)
 *
 * @name     numeric
 * @param    decimal      Decimal separator (e.g. '.' or ',' - default is '.')
 * @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(",");
 * @example  $(".numeric").numeric(null, callback);
 *
 */
jQuery.fn.numeric = function(decimal, callback)
{
	decimal = decimal || ".";
	callback = typeof callback == "function" ? callback : function(){};
	this.keypress(
		function(e)
		{
			var key = e.charCode ? e.charCode : e.keyCode ? e.keyCode : 0;
			// allow enter/return key (only when in an input box)
			if(key == 13 && this.nodeName.toLowerCase() == "input") {
				return true;
			} else if(key == 13) {
				return false;
			}
			
			//Special keys
			var allow = false;
			// allow Ctrl+A
			if((e.ctrlKey && key == 97 /* firefox */) || (e.ctrlKey && key == 65) /* opera */) return true;
			// allow Ctrl+X (cut)
			if((e.ctrlKey && key == 120 /* firefox */) || (e.ctrlKey && key == 88) /* opera */) return true;
			// allow Ctrl+C (copy)
			if((e.ctrlKey && key == 99 /* firefox */) || (e.ctrlKey && key == 67) /* opera */) return true;
			// allow Ctrl+Z (undo)
			if((e.ctrlKey && key == 122 /* firefox */) || (e.ctrlKey && key == 90) /* opera */) return true;
			// allow or deny Ctrl+V (paste), Shift+Ins
			if((e.ctrlKey && key == 118 /* firefox */) || (e.ctrlKey && key == 86) /* opera */ || (e.shiftKey && key == 45)) return true;
			
			// if not a number was not pressed
			if(key < 48 || key > 57) {
				/* '-' only allowed at start */
				if(key == 45 && this.value.length == 0) return true;
				/* only one decimal separator allowed */
				if(key == decimal.charCodeAt(0)) {
					//Decimal number, allow if not already in the field.
					allow = this.value.indexOf(decimal) == -1;
				} else if(
					// check for other keys that have special purposes
					key != 8 /* backspace */ &&
					key != 9 /* tab */ &&
					key != 13 /* enter */ &&
					key != 35 /* end */ &&
					key != 36 /* home */ &&
					key != 37 /* left */ &&
					key != 39 /* right */ &&
					key != 46 /* del */ ) {
					allow = false;
				} else {
					//For detecting special keys (listed above)
					// special keys have 'keyCode' and 'which' the same (e.g. backspace)
					// IE does not support 'charCode' and ignores them in keypress anyway
					if(typeof e.keyCode != "undefined" && e.keyCode == e.which && e.which != 0) {
						allow = true;
					} else if(typeof e.charCode != "undefined" && e.keyCode != 0 && e.charCode == 0 && e.which == 0) {
						// or keyCode != 0 and 'charCode'/'which' = 0
						allow = true;
					}
				}
			} else {
				allow = true;
			}
			return allow;
		}
	)
	.blur(
		function()
		{
			var val = jQuery(this).val();
			if(val != "")
			{
				var re = new RegExp("^\\d+$|\\d*" + decimal + "\\d+");
				if(!re.exec(val))
				{
					callback.apply(this);
				}
			}
		}
	);
	return this;
}