/*
 *
 * Copyright (c) 2006-2010 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 1.1.1
 * Demo: http://www.texotela.co.uk/code/jquery/numeric/
 *
 */
(function($) {
	/*
	 * 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);
	 *
	 */
	$.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;
				}
				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 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) || key == decimal.charCodeAt(1)) && this.containsDecimal)
					{
						allow = false;
					}
					// check for other keys that have special purposes
					if(
						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)
						// IE does not support 'charCode' and ignores them in keypress anyway
						if(typeof e.charCode != "undefined")
						{
							// special keys have 'keyCode' and 'which' the same (e.g. backspace)
							if(e.keyCode == e.which && e.which != 0)
							{
								allow = true;
							}
							// or keyCode != 0 and 'charCode'/'which' = 0
							else if(e.keyCode != 0 && e.charCode == 0 && e.which == 0)
							{
								allow = true;
							}
						}
					}
					// if key pressed is the decimal and it is not already in the field
					if(key == decimal.charCodeAt(0) || key == decimal.charCodeAt(1))
					{
						if(!this.containsDecimal)
						{
							allow = true;
							this.containsDecimal = true;
						}
						else
						{
							allow = false;
						}
					}
				}
				else
				{
					allow = true;
				}
				return allow;
			}
		)
				   
		.blur(
			function()
			{
				var val = $(this).val();
				if(val != "")
				{
					var re = new RegExp("^\\d+$|\\d*" + decimal + "\\d+");
					if(!re.exec(val))
					{
						callback.apply(this);
					}
				}
			}
		);
		
		this.keyup(
			function(e)
			{
				var key = e.charCode ? e.charCode : e.keyCode ? e.keyCode : 0;
				if(key == 8){
					if ((this.value.indexOf(decimal.charAt(0)) == -1) && (this.value.indexOf(decimal.charAt(1)) == -1))
						this.containsDecimal = false;
				}
				return true;
			}
		);
		return this;
	};

})(jQuery);