JavaScript Date.parse() Method
The Date.parse() method in JavaScript is a static method which is used to parse a string representation of a date and time and convert it into the number of milliseconds since January 1, 1970, 00:00:00 UTC (also known as the Unix Epoch). If the input string cannot be parsed, the method returns NaN (Not a Number).
The Epoch is the starting point for measuring time in seconds and is defined as January 1, 1970, 00:00:00 UTC.
Syntax
Following is the syntax of JavaScript Date parse() method −
date.parse(dateString);
The dateString will be the date string that we want to parse. It can be in different formats, such as "YYYY-MM-DD" or "YYYY-MM-DDTHH:mm:ss", and it can include time zone information.
Return Value
This method returns the number of milliseconds since January 1, 1970, 00:00:00 UTC (Unix Epoch) representing the date and time parsed from the input string.
Example 1
In the following example, we are passing the Date object to the JavaScript Date.parse() method −
<html> <body> <script> const currentDate = new Date(); const timestamp = Date.parse(currentDate); document.write(timestamp); </script> </body> </html>
Output
After executing, it returns time difference in milliseconds from epoch to the current date according to local time.
Example 2
In this example, we are calculating the difference in milliseconds from epoch to a specfic date "2023-12-27 12:30:00" −
<html> <body> <script> const dateString = '2023-12-27 12:30:00'; const timestamp = Date.parse(dateString); document.write(timestamp); </script> </body> </html>
Output
It returns "1703660400000" as output.
Example 3
Here, we are proving an invalid date to the Date.parse() method −
<html> <body> <script> const invalidDateString = 'This is not a date'; const timestamp = Date.parse(invalidDateString); document.write(timestamp); </script> </body> </html>
Output
It returns "NaN" as output.