jquery 判断当前设备是PC端还是移动端

$(function(){

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

    //检测平台
    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;
    }

})