自己写的一个小插件，还有很多需要完善。。。

 (function ($) {
    $.fn.StartLoading = function (option) {
        var defaultVal = {
            loadgif: ‘image/loading.gif‘,
            backcolor: ‘white‘,
            picheight: 50,
            picwidth: 50,
            fullshowpic: false,//图片是否设置透明度
            opacity: 0.5,
            timeout: 3000
        }
        var result = $.extend({}, defaultVal, option);
        var $obj = $(this);//选择器的Jquery对象
        var iswndordoc = false;
        if ($(this).get(0) == document || $(this).get(0) == window || $(this).get(0) == document.body) {
            iswndordoc = true;
            $obj = $(document.body);
        }
        //获取对象属性
        var constClone = {
            constwidth: $obj.width(),
            constheight: $obj.height(),
            constleft: iswndordoc == true ? 0 : $obj.offset().left,
            consttop: iswndordoc == true ? 0 : $obj.offset().top
        }
        if (iswndordoc) {
            var $clonebottom = $("<div></div>");
        } else {
            if ($(this)[0].tagName != "div") {
                var $objTemp = $("<div id=\"_temp_div\" style=\"width:" + constClone.constwidth + "; height:" + constClone.constheight + "; left:" + constClone.constleft + "; top:" + constClone.consttop + "\"></div>");
                $($obj.parent().get(0)).append($objTemp);
                $obj = $objTemp;
            }
            //生成最底层DIV
            var $clonebottom = $obj.clone().removeAttr("id").removeAttr("class").removeAttr("name");
        }

        //设置最底层DIV属性
        $clonebottom.removeClass().removeAttr("style").empty().css({
            "position": "absolute",
            "left": constClone.constleft,
            "top": constClone.consttop,
            "z_index": "10000",
            "width": constClone.constwidth,
            "height": constClone.constheight,
            "background-color": "transparent"
        });
        var $cloneTop = $clonebottom.clone().css({ "z_index": "9999", "background-color": "" + result.backcolor + "", "position": "" });
        $clonebottom.append($cloneTop);
        $clonebottom.append("<img id=\"_loading_plugin\" src=http://www.mamicode.com/"" + result.loadgif + "\" style=\"position:absolute;z_index: 9999\"/>");
        if (iswndordoc) {
            $obj.append($clonebottom);
        } else {
            $($obj.parent().get(0)).append($clonebottom);
        }
        var $imgloading = $("#_loading_plugin");
        $imgloading.css({ "width": "" + result.picwidth + "px", "height": "" + result.picheight + "px" });
        $imgloading.css({ "left": (constClone.constwidth - $imgloading.width()) / 2, "top": (constClone.constheight - $imgloading.height()) / 2 });
        if (result.fullshowpic)
            $clonebottom.css("opacity", "" + result.opacity + "");
        else
            $cloneTop.css("opacity", "" + result.opacity + "");
        var hand = setTimeout(function () {
            $clonebottom.fadeOut("slow", function () {
                $(this).remove();
                clearTimeout(hand);
            });
        }, result.timeout)
        return $clonebottom;
    }

    $.fn.StopLoading = function () {
        var $globalthis = $(this);
        $globalthis.remove()
    }
})(jQuery)

用法： 开始显示  var $load = $(window).StartLoading({ timeout: 1000000, fullshowpic: true }); 结束显示：  $load.StopLoading();

加载等待loading