JS 正在加载Loading插件

/**
* 脚本名称：页面加载Loading脚本
* 脚本说明：
* 1.因为使用到document.body.scrollHeight对象，脚本引入时，脚本应放到body内，否则报错；
* 2.loadingImage为loading的图片，您可以替换为您想要的图片；loading弹窗的样式可以通过代码修改； 
* 3.使用方法：弹出遮罩：rc.loading.add("加载中，请稍候", 1);扔掉遮罩： rc.loading.remove();
* 4.注意事项：请将此脚本引用在body标签内！！！
* 脚本作者：zhangqs008@163.com
* 
*/
var rc = window.rc || {};
rc.loading =
{
    add: function (title, opacity) {
        opacity = opacity == undefined ? 0.4 : opacity;
        var arr = this.getPageSize() || [];
        var width = 1440;
        var height = 900;
        if (arr.length >= 4) {
            width = parseInt(arr[2]);
            height = parseInt(arr[3]);
        }
        //var loadingImage = _basepath + "Admin/Scripts/jquery-easyui-1.4/themes/default/images/loading.gif";
        var loadingImage = "http://img.lanrentuku.com/img/allimg/1212/5-121204193943.gif";
        //背景遮罩
        var mask = document.createElement("div");
        mask.id = 'mask';
        mask.style.position = 'fixed';
        mask.style.left = '0';
        mask.style.top = '0';
        mask.style.width = '100%';
        mask.style.height = (arr.length > 1 ? parseInt(arr[1]) : 500) + "px";
        mask.style.background = "#F2F2F2";
        mask.style.filter = "alpha(opacity=" + opacity * 100 + ")";
        mask.style.opacity = opacity;
        mask.style.zIndex = "10000";
        try {
            mask.addEventListener('touchstart', function (e) { e.preventDefault(); }, false); //触摸事件
            mask.addEventListener('touchmove', function (e) { e.preventDefault(); }, false); //滑动事件
            mask.addEventListener('touchend', function (e) { e.preventDefault(); }, false); //离开元素事件
        } catch (e) { }
        if (document.body) {
            document.body.appendChild(mask);
        }
        //提示文本
        var loading = document.createElement("div");
        loading.id = 'loading';
        loading.style.position = 'absolute';
        loading.style.left = ((width / 2) - 75) + "px";
        loading.style.top = (height / 2 - 70) + "px";
        loading.style.width = '10em';
        loading.style.height = "28px";
        loading.style.lineHeight = "28px";
        loading.style.display = "inline-block";
        loading.style.padding = "0px 5px 0 25px";
        loading.style.fontSize = " 12px";
        loading.style.fontFamily = " initial";
        loading.style.zIndex = "100001";
        loading.style.background = "#fff url(" + loadingImage + ") no-repeat scroll 5px 5px";
        loading.style.border = "1px solid #ccc";
        loading.style.color = "#000";
        loading.style.borderRadius = "5px";
        title = (title != undefined && title.length > 0) ? title : "加载中，请稍候...";
        loading.innerHTML = title;
        if (document.body) {
            document.body.appendChild(loading);
        }
    },
    remove: function () {
        try {
            var element = document.getElementById("mask");
            element.parentNode.removeChild(element);
            
            element = document.getElementById("loading");
            element.parentNode.removeChild(element);
        } catch (e) {
            //console.log(e);
        }
    },
    getPageSize: function () {
        try {
            var xScroll, yScroll;
            if (window.innerHeight && window.scrollMaxY) {
                xScroll = window.innerWidth + window.scrollMaxX;
                yScroll = window.innerHeight + window.scrollMaxY;
            } else {
                if (document.body.scrollHeight > document.body.offsetHeight) { // all but Explorer Mac    
                    xScroll = document.body.scrollWidth;
                    yScroll = document.body.scrollHeight;
                } else { // Explorer Mac...would also work in Explorer 6 Strict, Mozilla and Safari    
                    xScroll = document.body.offsetWidth;
                    yScroll = document.body.offsetHeight;
                }
            }
            var windowWidth = 0;
            var windowHeight = 0;
            var pageHeight = 0;
            var pageWidth = 0;
            if (self.innerHeight) { // all except Explorer    
                if (document.documentElement.clientWidth) {
                    windowWidth = document.documentElement.clientWidth;
                } else {
                    windowWidth = self.innerWidth;
                }
                windowHeight = self.innerHeight;
            } else {
                if (document.documentElement && document.documentElement.clientHeight) { // Explorer 6 Strict Mode    
                    windowWidth = document.documentElement.clientWidth;
                    windowHeight = document.documentElement.clientHeight;
                } else {
                    if (document.body) { // other Explorers    
                        windowWidth = document.body.clientWidth;
                        windowHeight = document.body.clientHeight;
                    }
                }
            }
            // for small pages with total height less then height of the viewport    
            if (yScroll < windowHeight) {
                pageHeight = windowHeight;
            } else {
                pageHeight = yScroll;
            }
            // for small pages with total width less then width of the viewport    
            if (xScroll < windowWidth) {
                pageWidth = xScroll;
            } else {
                pageWidth = windowWidth;
            }
            var arrayPageSize = new Array(pageWidth, pageHeight, windowWidth, windowHeight);
            return arrayPageSize;
        } catch (e) { }
    }
};
window.onload = function () {
    rc.loading.remove();
};
rc.loading.add("", 1);