/*
*
* 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/
*
* $LastChangedDate$
* $Rev$
*/

/*
* 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;
}