The date.valueOf() is an inbuilt function in JavaScript which is used to get the number of milliseconds between 1 January 1970 00:00:00 UTC and the given date.
Syntax:
dateObj.valueOf()
Note: In the above syntax, DateObj is a valid Date object created using Date() conctructor whose contents are used to get the number of milliseconds between 1 January 1970 00:00:00 UTC and the given date as the contents of the Date() constructor.
- This function does not takes any parameter. It is just used along with a Date object created using Date() conctructor.
- It returns the number of milliseconds between 1 January 1970 00:00:00 UTC and the given date as the contents of the Date() constructor.
Parameters:
Return Values:
Below program illustrate the date.valueOf() function:-
<script> // Here a date has been assigned // while creating Date object var dateobj = new Date( 'October 15, 1996 05:35:32' ); // Getting the number of milliseconds between 1 January 1970 00:00:00 // UTC and the given date as the content of the above Date() constructor. var B = dateobj.valueOf(); // Printing the calculated number of milliseconds. document.write(B); </script> |
Output:
> 845337932000
- If nothing as parameter is passed while creating date object but still valueOf() function returns the number of milliseconds between 1 January 1970 00:00:00 UTC and the current date.
<script>
// Here nothing has been assigned
// while creating Date object
var
dateobj =
new
Date();
// Getting the number of milliseconds between 1 January 1970 00:00:00
// UTC and the current date.
var
B = dateobj.valueOf();
// Printing the calculated number of milliseconds.
document.write(B);
</script>
Output:
> 1524387231290
- Date of a month ranging between 1 to 31. If the date is taken as 35 which is out of the date range, it returns NaN i.e, not a number.
<script>
// Here a date has been assigned
// while creating Date object
var
dateobj =
new
Date(
'October 35, 1996 05:35:32'
);
// Getting the number of milliseconds between 1 January 1970 00:00:00
// UTC and the given date.
var
B = dateobj.valueOf();
// Printing the calculated number of milliseconds.
document.write(B);
</script>
Output:
> NaN
Errors and Exceptional cases associated with this function.
Some Important Points:
- Months, Dates, hours, minutes, seconds, milliseconds should all be in their respective range.Otherwise valueOf() function returns NaN i.e, not a number.
- Range of Months, Dates, hours, minutes, seconds, milliseconds are 0 to 11, 1 to 31, 0 to 23, 0 to 59, 0 to 59, 0 to 999 respectively.
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