//edition:20170623
//from:js高程(p198)
//获取视口宽高
var pageWidth = window.innerWidth,
	pageHeight = window.innerHeight;
if(typeof pageWidth !== "number"){
	//for lt IE 9
	if(document.compatMode === "CSS1Compat"){
		pageWidth = document.documentElement.clientWidth;
		pageWidth = document.documentElement.clientHeight;
	}else{
		pageWidth = document.body.clientWidth;
		pageHeight = document.body.clientHeight;
	}
}

//func: 获取location对象中的查询字符串参数
//edition: 20170623
//from: js高程(p207)
function getQueryStringArgs(){
	var qs = (location.search.length > 0)?location.search.substring(1):"",	
		//get query string and delete the start "?"
		args = {},	//to store args
		items = (qs.length > 0) ? qs.split("&") : [],
		item = null,
		name = "",
		value = "",
		i = 0,
		len = items.length;
	for(i = 0; i < len; i++){
		//add each item to args
		item = items[i].split("=");
		name = decodeURIComponent(item[0]);
		value = decodeURIComponent(item[1]);
		args[name] = value;
	}
	return args;
}

//func: 插件检测
//edition: 20170623
//from: js高程(p212) (modified)
function hasPlugin(name){
	if(typeof name !== "string"){
		return false;
	}
	var identifier = "";

	switch(name.toLowerCase()){
		//get the plugin's identifier in IE arrording to name
		case flash:
			identifier = "ShockwaveFlash.ShockwaveFlash";
			break;
		case quicktime:
			identifier = "QuickTime.QuickTime";
			break;
	}

	var result = hasNotIEPlugin(name);
	if(!result){
		result = hasIEPlugin(identifier);
	}
	return result;
}

function hasIEPlugin(identifier){
	try{
		new ActiveXObject(identifier);
		return true;
	}catch(ex){
		return false;
	}
}

function hasNotIEPlugin(name){
	name = name.toLowerCase();
	for(var i = 0; i < navigator.plugins.length; i++){
		if(navigator.plugins[i].name.toLowerCase().indexOf(name) > 0){
			return true;
		}
	}
	return false;
}

//func: 检测object对象是否具有property属性
//edition: 20170623
//from: js高程(p219) (modified)
function isHostMethod(object,property){
	var t = typeof object[property];
	t = t.toLowerCase();
	return t === "function" ||
			(!!(t === "object" && boject[property])) ||
			t === "unknown";
}

//func: 获取元素相对视窗的左偏移和上偏移量
//edition: 20170628
//from: js高程（p321）
//question: 应该差一个边框宽度

function getElementLeft(element){
	var actualLeft = element.offsetLeft,
		current = element.offsetParent;
	while(current !== null){
		actualLeft += current.offsetLeft;
		current  = current.offsetParent;
	}

	return actualLeft;
}
function getElementTop(element){
	var actualTop = element.offsetTop,
		current = element.offsetParent;
	while(current !== null){
		actualTop += current.offsetTop;
		current  = current.offsetParent;
	}

	return actualTop;

}

//func: 获取视窗大小
//edition: 20170628
//from: js高程（p323）
function getViewport(){
	if(document.compatMode === "BackCompat"){
		return {
			width: document.body.clientWidth,
			height: document.body.clientHeight
		};
	}else{
		return {
			width: document.documentElement.clientWidth,
			height: document.documentElement.clientHeight
		};
	}
}

//func: 获取元素相对视口的位置
//edition: 20170628
//from: js高程（p325）
function getBoundingClientRect(element){
	var scrollTop = document.documentElement.scrollTop,
		scrollLeft = document.documentElement.scrollLeft;

	if(element.getBoundingClientRect){
		if(typeof auguments.callee.offset !== "number"){
			var temp = document.createElement("div");
			temp.style.cssText = "position: absolute; left: 0; top: 0";
			document.body.appendChild(temp);
			arguments.callee.offset = -temp.getBoundingClientRect().top - scrollTop;
			document.body.removeChild(temp);
			temp = null;
		}
		var rect = element.getBoundingClientRect(),
			offset = arguments.callee.offset;
		return {
			left: rect.left + offset,
			right: rect.right + offset,
			top: rect.top + offset,
			bottom: rect.bottom + offset
		};
	}else{
		var actualTop = getElementTop(element),
			actualLeft = getElementLeft(element);
		return {
			left: actualLeft - scrollLeft,
			rigth: actualLeft + offsetWidth - scrollLeft,
			top: actualTop - scrollTop,
			bottom: actualTop + offsetHeight - scrollTop 
		};
	}
}

// 对Date的扩展，将 Date 转化为指定格式的String
// 月(M)、日(d)、小时(h)、分(m)、秒(s)、季度(q) 可以用 1-2 个占位符，
// 年(y)可以用 1-4 个占位符，毫秒(S)只能用 1 个占位符(是 1-3 位的数字)
// 例子：
// (new Date()).format("yyyy-MM-dd hh:mm:ss.S") ==> 2019-01-03 21:21:02.760
// (new Date()).format("yyyy-M-d h:m:s.S")      ==> 2019-1-3 21:21:10.291
Date.prototype.format = function (fmt) {
    var o = {
        "M+": this.getMonth() + 1, //月份
        "d+": this.getDate(), //日
        "h+": this.getHours(), //小时
        "m+": this.getMinutes(), //分
        "s+": this.getSeconds(), //秒
        "q+": Math.floor((this.getMonth() + 3) / 3), //季度
        "S": this.getMilliseconds() //毫秒
    };
    if (/(y+)/.test(fmt)) fmt = fmt.replace(RegExp.$1, (this.getFullYear() + "").substr(4 - RegExp.$1.length));
    for (var k in o)
        if (new RegExp("(" + k + ")").test(fmt)) fmt = fmt.replace(RegExp.$1, (RegExp.$1.length == 1) ? (o[k]) : (("00" + o[k]).substr(("" + o[k]).length)));
    return fmt;
};