JS 技巧积累

判断是否存在于


var a = "b" in c;

字符串转数组新写法


var split = "split",S = " ",    events = "click dblclick mousedown mousemove mouseout mouseover mouseup touchstart touchmove touchend touchcancel"[split](S);

var h = 2;h = ~~h;//怎么理解？