var deadline = new Date(2014, 1, 2);

var today = new Date();

​

var monthDiff = deadline.getMonth() - today.getMonth();

​

if (monthDiff < 3) {

  console.log('Deadline is in 3 months or less!');

}

​

if (monthDiff <= 1) {

  console.log('Deadline is in 1 month or less!'); 

}