var CalAge = Class.create();
CalAge.prototype = Object.extendsObject(global.AbstractAjaxProcessor, {
	generateAge: function() {
		var dob = this.getParameter('sysparam_id');
		var today = new GlideDateTime();
		var todayYear = today.getYearLocalTime();
		var bday = new GlideDateTime(dob.toString());
		var bdayYear = bday.getYearLocalTime();
		var age =todayYear - bdayYear;
		return age;
	},
	type: 'CalAge'
});

/** To run tyhe above code type the following code in Background script and run
var dob1 = new CalAge.generateAge('23-07-2017');
gs.print(dob1);
**/