201507231141_《JavaScript——位掩码技术》

var OPTION_A = 1;
var OPTION_B = 2;
var OPTION_C = 4;
var OPTION_D = 8;
var OPTION_E = 16;

var options = OPTION_A | OPTION_C | OPTION_D;

//1
if (options & OPTION_A){
//do something
}
//2
if (options & OPTION_B){
//do something
}