sleep 函数作用是让线程休眠，等到指定时间在重新唤起。function sleep(delay) {
var start = (new Date()).getTime();
while ((new Date()).getTime() - start < delay) {
continue;
}
}
function test() {
console.log('111');
sleep(2000);
console.log('222');
}
test() 方法二：定时器 function sleep1(ms, callback) {
……