In Javascript , getTime() method return the numeric value ( in milliseconds ) corresponding to the time for the specified data according to universal time . Through this method you can assign a date and time to another Date Object. Basically this method is equivalent( functionally ) to the valueOf ( ) method .< br> Syntax :

dateObj.getTime() //  There is no parameter 

Return value >
Return number of milliseconds since 1 January 1970 .
Example ->
1) to copy the data with the help of getTime() method

var dob = new Date( 1994 , 09 , 17 ) ;
var copydob = new Date () ;
copy.setTime(dob.getTime());// in this birthday will be copied

2) To measure the execution time -> We can measure the execution time by subtraction two consecutive getTime( ) calls . This can be used to calculate the executing times of some operations. Let's understand by example

var start , end , i
start = new Date();
for( i = 0 ; i < 1000 ; i++){
Math.sqrt(i);
}
end = new Date();
document.write ( "operation" + (end.getTime() - start.getTime()) + "msec"); // output will come in milliseconds

If you want your result in Years instead of milliseconds then you can do by dividing the milliseconds to years .