JavaScript | Adding hours to the Date object

Given a date, the task is to add hours to it. To add hours to date in javascript, we’re going to discuss a few techniques. First few methods to know.

  • JavaScript getHours() Method
    This method returns the hour (from 0 to 23) of the provided date and time.
    Syntax:

    Date.getHours()
    

    Return value:
    It returns a number, from 0 to 23, representing the hour.

  • JavaScript setHours() Method
    This method sets the hour of a date object.
    We can also set the minutes, seconds and milliseconds.
    Syntax:

    Date.setHours(hour, min, sec, millisec)
    

    Parameters:

    • hour: This parameter is required. It specifies the integer representing the hour. Values expected are 0-23, but other values are allowed.
    • min: This parameter is optional. It specifies the integer representing the minutes. Values expected are 0-59, but other values are allowed.
    • sec: This parameter is optional. It specifies the integer representing the seconds. Values expected are 0-59, but other values are allowed.
    • millisec: This parameter is optional. It specifies the integer representing the milliseconds. Values expected are 0-999, but other values are allowed.

    Note:
    All the previous 4 parameters accept values apart from their range and these values adjust like.



    • hour = -1, means the last hour of the previous day and same for the other parameters.
    • if min passed is 60, means the first minute of the next hour and same for the other parameters.

    Return value:
    It returns a number, denoting the number of milliseconds between the date object and midnight January 1, 1970.

  • JavaScript getTime() method
    This method returns the number of milliseconds between midnight of January 1, 1970, and the specified date.
    Syntax:

    Date.getTime()
    

    Return value:
    It returns a number, representing the number of milliseconds since midnight January 1, 1970.

  • JavaScript setTime() method
    This method set the date and time by adding/subtracting a defines number of milliseconds to/from midnight January 1, 1970.
    Syntax:

    Date.setTime(millisec)
    

    Parameters:

    • millisec: This parameter is required. It specifies the number of milliseconds to be added/subtracted, midnight January 1, 1970

    Return value:
    It returns, representing the number of milliseconds between the date object and midnight January 1 1970.