JS与，或运算DEMO

var a = 0x1;
var b = 0x2;
var c = 0x4;
var d = a | b; //d是由a,b加起来

//判断d是由a，b，c哪些加起来

d & a == a; //是否包换a
d & b == b;//是否包换b
d & c == c;//是否包换c