JSFiddle - React, Tailwind, and code Playground

HTML

<a href="https://gc.synxis.com/rez.aspx?Hotel=27648&amp;Chain=16841&amp;rate=CEL">BOOK THIS PACKAGE</a>
<br>
<a href="https://gc.synxis.com/rez.aspx?Hotel=27648&Chain=16841&rate=CEL&_ga=1.167887777.1485492925.1446983479">Book Now</a>
<br>
<a href="https://gc.synxis.com/rez.aspx?hotel=27648&Chain=16841&_ga=1.60014637.1485492925.1446983479">Book Now</a>
<br>
<a href="http://www.google.com">GOOGLE</a>

JavaScript

jQuery('a[href*="gc.synxis.com"]').attr('href', function(i,href) {
       	var requiredDate = new Date();
		var numberOfDaysToAdd = 60;
		requiredDate.setDate(requiredDate.getDate() + numberOfDaysToAdd); 
		var month 	= requiredDate.getMonth()+1;
		var day 	= requiredDate.getDate();
		var output = requiredDate.getFullYear() + '/' + ((''+month).length<2 ? '0' : '') + month + '/' + ((''+day).length<2 ? '0' : '') + day;
       	this.href += '&arrive='+output;
	});