expire code

Can someone please help me with this question? I am using this code to expire the document on a specific day and year. What occurred to me and is the reason I'm asking this question, can this script be modified to expire on a specific day and year but also expire on any date prior and any date passed the specific date. Example, to expire on December 25, 2017. If the user tries to change their computer's calendar to, let's say, 2016 the document would still expire.

This is the script I'm using and works ok, but I'd like to modify it to make it more difficult to bypass even if the user turns off "Enable Javascript" or sets their computer back.

function Expire()

{

// Get the current date and time

var rightNow = new Date();

// Setup End Date

var rightNow = new Date();

var beginDate = new Date("March 21, 2016 06:15:00 AM");

var endDate = new Date("March 31, 2017 1:57:00 PM");

this.closeDoc(true)

}

}

// execute check expiration code

Expire();