Show a qrcode image on browser lower right | left corner

sqrcode.js

/**
 * @fileOverview Show a qrcode image on browser lower right | left corner
 * @author ra <ra@rockagen.com>
 * @version 0.0.1
 * @see {@link http://usejsdoc.org|jsdoc}
 *
 *
 * @example
 *
 *	qrsource:{
 *		img: img url
 *		href: link url
 *	}
 *
 *	pos: default lower right corner,if pos is undefined.
 *
 * -------------------------------------------------------------------------
 *
 *  sqrcode(qrsource,  pos)
 *
 *
 *  sqrcode({
 *		img:"http://img3.cache.netease.com/news/2012/qr_newapp.png",
 *		href:"http://m.163.com/newsapp/"
 *	});
 *
 *  or
 *
 *  sqrcode({
 *		img:"http://img3.cache.netease.com/news/2012/qr_newapp.png",
 *		href:"http://m.163.com/newsapp/"
 *	},1);
 */

/** @namespace 
 */
var sqrcode=function(qrsource,pos){

	if (typeof qrsource == "undefined") 
		qrsource = {};

	if (typeof qrsource.img == "undefined") 
		qrsource.img="xxx.png";

	if (typeof qrsource.href == "undefined")
		qrsource.href="#";

	var version = window.navigator.appVersion;
	var isIE6 = (version.indexOf("MSIE 6.0") != -1 || version.indexOf("MSIE 5.5") != -1)? true:false;

	function showQR(top){
		var QRbox= document.createElement("div");
		var QRboxCSS ={
			'width': "110px",
			'height': "147px",
			'position': "fixed",
			'_position': "absolute",
			'top': top + "px",
			'display':"block",
			'zIndex':100
		};

		for(var key in QRboxCSS){
			QRbox.style[key] = QRboxCSS[key];
		}

		if(!!pos){
			QRbox.style.left="3px";
		}else{
			QRbox.style.right="3px";
		}

		if(isIE6){
			QRbox.style.position = "absolute";
		}

		QRbox.innerHTML="<a href='"+qrsource.href+"' target='_blank'></a>";
		var link =QRbox.getElementsByTagName("a")[0];
		var linkCSS = {
			display:"block",
			width: "100%",
			height: "100%",
			backgroundImage: "url("+qrsource.img+")",
			backgroundPosition: "0px 0px"
		};
		for(var key1 in linkCSS){
			link.style[key1] = linkCSS[key1];
		}
		document.body.appendChild(QRbox);
		var linkEventMap = {
			"mouseover": function(){
				link.style.backgroundPosition = "-110px 0px";
			},
			"mouseout": function(){
				link.style.backgroundPosition = "0px 0px";
			}
		};
		for(var evt in linkEventMap){
			var func = linkEventMap[evt];
			addEvent(evt, link, func);
		}
		addEvent("scroll", window, function(){
			if(isIE6){
				QRbox.style.top = getScrollTop() + top + "px";
			}
		});
	}

	function addEvent(evt, elem, callback){
		if(elem.addEventListener){
			elem.addEventListener(evt, callback, false);
		} else {
			elem.attachEvent && elem.attachEvent("on"+evt, callback);
		} 
	}
	function getScrollTop(){
		if(typeof pageYOffset!= 'undefined'){
			//most browsers
			return pageYOffset;
		}
		else{
			var B= document.body; //IE 'quirks'
			var D= document.documentElement; //IE with doctype
			D= (D.clientHeight)? D: B;
			return D.scrollTop;
		}
	}

	return showQR(500);
};