Skip to content
Related Articles

Related Articles

Improve Article

JavaScript performance.now() Method

  • Last Updated : 04 Mar, 2021

In JavaScript perfromance.now() method can be used to check the performance of your code. You can check the execution time of your code using this method.

It returns the value of time (of type double) in milliseconds. The returned value represents the time elapsed since the execution started.

Syntax:

let t = performance.now();

The code below will give you a brief idea of how this code performs.

Example 1:



Javascript




<script>
  const t0 = performance.now();
  for (let i = 0; i < 10; i++) {
    console.log(i);
  }
  const t1 = performance.now();
  console.log(`Call to doSomething took ${t1 - t0} milliseconds.`);
</script>

Output: In the above code, variables t0 and t1 are used to store starting time and ending time respectively, and while printing we subtracted t0 from t1 to print the time required in the execution of the code.

0
1
2
3
4
5
6
7
8
9
"Call to doSomething took 1.7899998929351568 milliseconds."

Example 2:

Javascript




<script>
  const t0 = performance.now();
  for (let i = 0; i < 5; i++) {
    console.log(i);
  }
  const t1 = performance.now();
  console.log(`Call to doSomething took ${t1 - t0} milliseconds.`);
</script>

Output:

0
1
2
3
4
"Call to doSomething took 0.7100000511854887 milliseconds."
My Personal Notes arrow_drop_up
Recommended Articles
Page :