jQuery中toggle方法实现点击切换

     // toggle方法
        $.fn.toggle = function( fn, fn2 ) {
            let args = arguments,guid = fn.guid || $.guid++,i=0,
                toggler = function( event ) {
                    let lastToggle = ( $._data( this, "lastToggle" + fn.guid ) || 0 ) % i;
                    $._data( this, "lastToggle" + fn.guid, lastToggle + 1 );
                    event.preventDefault();
                    return args[ lastToggle ].apply( this, arguments ) || false;
                };
            toggler.guid = guid;
            while ( i < args.length ) {
                args[ i++ ].guid = guid;
            }
            return this.click( toggler );
        };
        $("#fullScreen").toggle(function(){
            $(this).css("background","url('resources/images/zoom_control.png') no-repeat 11px -170px");
        },function(){
            $(this).css("background","url('resources/images/zoom_control.png') no-repeat 10px 11px");
        });