JavaScript | Date.parse()

The Date.parse() function is an inbuilt function in JavaScript which helps us to know the exact number of milliseconds that have passed since midnight, January 1, 1970, till the date we provide.
Syntax:

Date.parse(datestring);

Parameters: This function takes a parameter of datestring which is taken as the input.
Return Values: It returns an integer value representing the number of millisecond between midnight January 1, 1970, and the date provided. If by any means, the machine can’t recognize the string or the input string is invalid, it will return “NaN” instead of an integer.
JavaScript code to show the working of Date.parse() function:
Example 1:

filter_none

edit
close

play_arrow

link
brightness_4
code

<script>
  
    // Taking a date string as input.
    var date = "February 18, 2018 12:30 PM";
      
    // Calling parse function on input date string.
    var msec = Date.parse(date);
    document.write(msec);
      
</script>

chevron_right


Output:



1518937200000

Example 2:
If the input string of date is not correct, it return NaN i.e, not a number.

filter_none

edit
close

play_arrow

link
brightness_4
code

<script>
  
    // Taking wrong date string as input.
    var date = "February 48, 2018 12:30 PM";
      
    // calling parse function.
    var msec = Date.parse(date);
    document.write(msec);
      
</script>                    

chevron_right


Output:

NaN

Why 01 Jan 1970 00:00:00 GMT?
It is called the Unix time i.e. the time Unix was invented. Almost all the programming languages, operating systems use this as their reference starting time.
Note: Once we get the millisecond count between two dates, we can easily find the number of hours, days, months, years, etc by simple maths calculation.

Supported Browsers: The browsers supported by JavaScript Date.parse()() Function are listed below:

  • Google Chrome
  • Internet Explorer
  • Firefox
  • Opera
  • Safari


My Personal Notes arrow_drop_up

Check out this Author's contributed articles.

If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to contribute@geeksforgeeks.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.

Please Improve this article if you find anything incorrect by clicking on the "Improve Article" button below.