jquery遮罩层

    (function () {
            //遮罩层实现 zhe zhao ceng kexb 2016.2.24
            $.extend($.fn, {
                mask: function (msg, maskDivClass) {
                    this.unmask();
                    // 参数
                    var op = {
                        opacity: 0.8,
                        z: 10000,
                        bgcolor: '#ccc'
                    };
                    var original = $(document.body);
                    var position = { top: 0, left: 0 };
                    if (this[0] && this[0] !== window.document) {
                        original = this;
                        position = original.position();
                    }
                    // 创建一个 Mask 层，追加到对象中
                    var maskDiv = $('<div class="maskdivgen">&nbsp;</div>');
                    maskDiv.appendTo(original);
                    var maskWidth = original.outerWidth();
                    if (!maskWidth) {
                        maskWidth = original.width();
                    }
                    var maskHeight = original.outerHeight();
                    if (!maskHeight) {
                        maskHeight = original.height();
                    }
                    maskDiv.css({
                        position: 'absolute',
                        top: position.top,
                        left: position.left,
                        'z-index': op.z,
                        width: "100%",//maskWidth,
                        height:"30%", //maskHeight,
                        'background-color': op.bgcolor,
                        opacity: 0
                    });
                    if (maskDivClass) {
                        maskDiv.addClass(maskDivClass);
                    }
                    if (msg) {
                        var msgDiv = $('<div style="position:absolute;border:#6593cf 1px solid; padding:2px;background:#ccca"><div style="line-height:24px;border:#a3bad9 1px solid;background:white;padding:2px 10px 2px 10px">' + msg + '</div></div>');
                        msgDiv.appendTo(maskDiv);
                        var widthspace = (maskDiv.width() - msgDiv.width());
                        var heightspace = (maskDiv.height() - msgDiv.height());
                        msgDiv.css({
                            cursor: 'wait',
                            top: (heightspace / 2 - 2),
                            left: (widthspace / 2 - 2)
                        });
                    }
                    maskDiv.fadeIn('fast', function () {
                        // 淡入淡出效果
                        $(this).fadeTo('slow', op.opacity);
                    })
                    return maskDiv;
                },
                unmask: function () {
                    var original = $(document.body);
                    if (this[0] && this[0] !== window.document) {
                        original = $(this[0]);
                    }
                    original.find("> div.maskdivgen").fadeOut('slow', 0, function () {
                        $(this).remove();
                    });
                }
            });
        })();