我在这里有什么时间？

Question

If the answer is 8. What is 8? milliseconds? or must I (time/100)-(ntime/100) to get milliseconds?

var time=(+new Date());

for(var i=0;i<100;i++){/*something intensive*/}

var ntime=(+new Date());

console.log('answer: '+((ntime)-time)+('( '+time+' , '+ntime+' )'));

answer: 8 / 1404573120333 >> 1404573120341

(+new Date()) A unix timestamp is described as the time in seconds since the epoch

Answer 1

1404573825 would be epoch, seconds since jan1,1970.

1404573120333 is 3 digits longer, most likely milliseconds since jan1,1970

difference therefore too.

Answer 2

When turning the Date value into a number using the + operator, it will call the valueOf method . The value returned is the number of milliseconds since 1970-01-01 UTC.

"The valueOf method returns the primitive value of a Date object as a number data type, the number of milliseconds since midnight 01 January, 1970 UTC."

The valueOf method returns the same value as the getTime method . The doumentation for the getTime method has this example for measuring time in milliseconds:

var end, start;

start = new Date();
for (var i = 0; i < 1000; i++)
  Math.sqrt(i);
end = new Date();

console.log("Operation took " + (end.getTime() - start.getTime()) + " msec");