谁能给我解释下这段javascript extjs代码

谁能给我解释下这段javascript extjs代码

Ext.ns("App");

App.init = function () {

Ext.QuickTips.init();

//主框架

var main = new IndexPage();

};//初始化

App.showMask = function() {//遮罩的显示

if (!this.loadMask) {

this.loadMask = new Ext.LoadMask(Ext.getBody());

this.loadMask.show();

}

};

//遮罩的隐藏

App.hideMask = function() {

if (this.loadMask) {

this.loadMask.hide();

this.loadMask = null;

}

};

//获取一个当前tab的大小

App.getCurrentSize = function(){

var comSize={height:0,width:0};

var tabPanel = Ext.getCmp('centerTabPanel');

var h = tabPanel.getInnerHeight();

var w = tabPanel.getInnerWidth();

comSize.height=h-1;

comSize.width=w-1;

return comSize;

};

//获取一个当前tab的高度

App.getCurrentHeight = function(){

var comSize = this.getCurrentSize();

return comSize.height;

};

App.getCurrentWidth = function(){

var comSize = this.getCurrentSize();

return comSize.width;

};

//设置cookie值

App.setCookie = function(name, value, day){//三个参数，一个是cookie的名字，一个是值，一个保存天数

var Days = day; //此 cookie 将被保存的天数

var exp = new Date(); //new Date("December 31, 9998");

exp.setTime(exp.getTime() + Days * 1 * 60 * 60 * 1000);

document.cookie = name + "=" + escape(value) + ";expires=" + exp.toGMTString();

}

App.getCookie = function(name){//取cookies函数

var arr = document.cookie.match(new RegExp("(^| )" + name + "=([^;]*)(;|$)"));

if (arr != null)

return unescape(arr);

return null;

};

////退出

App.Logout = function() {

window.location.href = "/MyStock/login.jsp";

};

//注销系统

App.logoutSystem = function(){

if ( window.confirm("你确定要注销系统吗? ")) {

window.parent.location.href="../zuxiao.jsp";

}

};

Ext.onReady(App.init);//首先调用init方法