/**
*  Dual licensed under the MIT (MIT-LICENSE.txt)
*  and GPL (GPL-LICENSE.txt) licenses.
**/
var allowConfirm = true;



(function($) {

    $.fn.extend({
        FormObserve: function(opt) {
            opt = $.extend({
                changeClass: "changed",
                filterExp: "",
                msg: "Unsaved changes will be lost."
            }, opt || {});

            var fs = $(this);
            fs.each(function() {
                this.reset();
                var f = $(this);
                var is = f.find(':input');
                f.FormObserve_save();
                setInterval(function() {
                    is.each(function() {
                        var node = $(this);
                        var def = $.data(node.get(0), 'FormObserve_Def');
                        if (node.FormObserve_ifVal() == def) {
                            if (opt.changeClass) node.removeClass(opt.changeClass);
                        } else {
                            if (opt.changeClass) node.addClass(opt.changeClass);
                        }
                    });
                }, 1);
            });

            function beforeunload(e) {
                if (allowConfirm) {
                    var changed = false;
                    fs.each(function() {
                        if ($(this).find(':input').FormObserve_isChanged()) {
                            changed = true;
                            return false;
                        }
                    });
                    if (changed) {
                        e = e || window.event;
                        e.returnValue = opt.msg;
                    }
                }
            }
            if (window.attachEvent) {
                window.attachEvent('onbeforeunload', beforeunload);
            } else if (window.addEventListener) {
                window.addEventListener('beforeunload', beforeunload, true);
            }
        },
        FormObserve_save: function() {
            var node = $(this);
            if (node.is('form')) {
                node.find(':input').each(function() {
                    $(this).FormObserve_save();
                });
            } else if (node.is(':input')) {
                $.data(node.get(0), 'FormObserve_Def', node.FormObserve_ifVal());
            }
        },
        FormObserve_isChanged: function() {
            var changed = false;
            this.each(function() {
                var node = $(this);
                if (node.eq(':input')) {
                    var def = $.data(node.get(0), 'FormObserve_Def');
                    if (typeof def != 'undefined' && def != node.FormObserve_ifVal()) {
                        changed = true;
                        return false;
                    }
                }
            });
            return changed;
        },
        FormObserve_ifVal: function() {
            var node = $(this.get(0));
            if (node.is(':radio,:checkbox')) {
                var r = node.attr('checked');
            } else if (node.is(':input')) {
                var r = node.val();
            }
            return r;
        }
    });
})(jQuery);