JavaScript判斷瀏覽器和hack滾動條的寫法

var userAgent = navigator.userAgent; //取得瀏覽器的userAgent字符串 
 var isOpera = userAgent.indexOf("Opera") > -1; //判斷是否Opera瀏覽器 
 var isIE = userAgent.indexOf("compatible") > -1 && userAgent.indexOf("MSIE") > -1 && !isOpera; //判斷是否IE瀏覽器 
 var isEdge = userAgent.indexOf("Edge") > -1 && !isIE; //判斷是否IE的Edge
 var?isFF?=?userAgent.indexOf("Firefox")>-1 //判斷是否Firefox瀏覽器??
 var?isSafari?=?userAgent.indexOf("Safari")>-1&&?userAgent.indexOf("Chrome")==-1; //判斷是否Safari瀏覽器??
 var?isChrome?=?userAgent.indexOf("Chrome")>-1&&?userAgent.indexOf("Edge")==-1; //判斷Chrome瀏覽器?？

if(isFF){
 console.log('火狐')
 $('#parent').width((windowWidth -320)*(1.01749));
 }else if(isChrome){ 
 console.log('谷歌')
 $('#parent').width((windowWidth -320)*(1.01749));
 }else if(isIE){ 
 console.log('ie10-ie5')
 $('#parent').width((windowWidth -320)*(1.01720));
 }else if(isEdge){
 console.log('edge')
 $('#parent').width((windowWidth -320)*(1.02224));
 }else{
 console.log('ie11和其他瀏覽器')
 $('#parent').width((windowWidth -320)*(1.01816));
 }