-_-#setTimeout / setInterval

function sleep(milliSeconds) {
var startTime = new Date().getTime()
while (new Date().getTime() < startTime + milliSeconds) {}
}

var i = 0
setInterval(function() {
console.log(+new Date(), ++i)
sleep(4000)
}, 2000)
/*
间隔4s左右
1395043279715 1
1395043283750 2
1395043287753 3
1395043291757 4
1395043295763 5
1395043299763 6
*/

/*setTimeout(function() {
console.log(+new Date(), ++i)
sleep(4000)
setTimeout(arguments.callee, 2000)
}, 2000)
*/
/*
间隔6s左右
1395042762150 1
1395042768158 2
1395042774169 3
1395042780177 4
1395042786177 5
1395042792177 6
*/