/*
*
* Copyright (c) 2006 Sam Collett (http://www.texotela.co.uk)
* Licensed under the MIT License:
* http://www.opensource.org/licenses/mit-license.php
* 
*/

/*
* 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;
		    }
		    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) && this.value.indexOf(decimal) != -1) {
		            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) && this.value.indexOf(decimal) == -1) {
		            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;
}