Convert UNIX timestamp to local time with timezone UTC+/- code

convert-UNIX-timestamp.js

function convertTimestamp(timestamp) {
  var d = new Date(timestamp * 1000),	// Convert the passed timestamp to milliseconds
		yyyy = d.getFullYear(),
		mm = ('0' + (d.getMonth() + 1)).slice(-2),	// Months are zero based. Add leading 0.
		dd = ('0' + d.getDate()).slice(-2),			// Add leading 0.
		hh = d.getHours(),
		h = hh,
		min = ('0' + d.getMinutes()).slice(-2),		// Add leading 0.
		ampm = 'AM',
		time;
			
	if (hh > 12) {
		h = hh - 12;
		ampm = 'PM';
	} else if (hh === 12) {
		h = 12;
		ampm = 'PM';
	} else if (hh == 0) {
		h = 12;
	}
	
	// Added timezone
	tz = d.getTimezoneOffset();
	
	if(tz==0)
		tzs = ' UTC';
	else if(tz>0)
		tzs = ' UTC-';
	else
		tzs = ' UTC+';
	
	// get absolute value
	tz = Math.abs(tz);
	
	tzhh = Math.floor(tz/60);
	
	tzmm = tz - tzhh*60;
	if(tzmm==0)
		tzmm = '00';
	
	// ie: 2013-02-18, 8:35 AM (Added UTC+8:00)
	time = yyyy + '-' + mm + '-' + dd + ', ' + h + ':' + min + ' ' + ampm + ' ' + tzs + tzhh + ':' + tzmm;
		
	return time;
}