jquery 判斷當前設備是PC端還是移動端

$(function(){

 var system = {
 win: false,
 mac: false,
 xll: false,
 ipad:false
 };

 //檢測平台
 var p = navigator.platform;

 system.win = p.indexOf("Win") == 0;
 system.mac = p.indexOf("Mac") == 0;
 system.x11 = (p == "X11") || (p.indexOf("Linux") == 0);
 system.ipad = (navigator.userAgent.match(/iPad/i) != null)?true:false;

 if (system.win || system.mac || system.xll ||system.ipad) {
 
 } else {

 some code;
 }

})