These patterns are converted into links to UPS (http://www.ups.com):

• 1Z 999 999 99 9999 999 9

• 9999 9999 999

• T999 9999 999

This pattern is converted into a link to FedEx (http://www.fedex.com):

• 9999 9999 9999

The following patterns are converted into links to the United States Postal Service (http://www.usps.com):

• 9999 9999 9999 9999 9999 99

• 9999 9999 9999 9999 9999

Save the following user script as tracking-linkify.user.js:

	// ==UserScript==
	// @name UPS/FedEx Tracking Linkify
	// @namespace http://scripts.slightlyinsane.com
	// @description Link package tracking numbers to appropriate site
	// @include *
	// ==/UserScript==

	// Based on code by Justin Novack and Logan Ingalls
	// and included here with their gracious permission
	// Originally licensed under a Create Commons license
	// Visit http://creativecommons.org/licenses/by-sa/2.0/ for details

	var UPSRegex = new RegExp('/\b(1Z ?[0-9A-Z]{3} ?[0-9A-Z]{3} ?[0-9A-Z]{'+
	'2} ?[0-9A-Z]{4} ?[0-9A-Z]{3} ?[0-9A-Z]|[\\dT]\\d\\d\\d ?\\d\\d\\d\\d '+
	'?\\d\\d\\d)\\b', 'ig');
	var FEXRegex = new RegExp('\\b(\\d\\d\\d\\d ?\\d\\d\\d\\d ?\\d\\d\\d\\'+
	'd)\\b', 'ig');
	var USARegex = new RegExp('\\b(\\d\\d\\d\\d ?\\d\\d\\d\\d ?\\d\\d\\d\\'+
	'd ?\\d\\d\\d\\d ?\\d\\d\\d\\d ?\\d\\d|\\d\\d\\d\\d ?\\d\\d\\d\\d ?\\d'+
	'\\d\\d\\d ?\\d\\d\\d\\d ?\\d\\d\\d\\d)\\b', 'ig');

	function UPSUrl(t) {
		return 'http://wwwapps.ups.com/WebTracking/processInputRequest?sor'+
			't_by=status&tracknums_displayed=1&TypeOfInquiryNumber=T&loc=e'+
			'n_US&InquiryNumber1=' + String(t).replace(/ /g, '') +
			'&track.x=0&track.y=0';
	}

	function FEXUrl(t) {
		return 'http://www.fedex.com/cgi-bin/tracking?action=track&languag'+
			'e=english&cntry_code=us&initial=x&tracknumbers=' +
			String(t).replace(/ /g, '');
	}

	function USAUrl(t) {
	return 'http://trkcnfrm1.smi.usps.com/netdata-cgi/db2www/cbd_243.d'+

		'2w/output?CAMEFROM=OK&strOrigTrackNum=' +
		String(t).replace(/ /g, '');
	}

	// tags we will scan looking for un-hyperlinked urls
	var allowedParents = [
		'abbr', 'acronym', 'address', 'applet', 'b', 'bdo', 'big',
		'blockquote', 'body', 'caption', 'center', 'cite', 'code',
		'dd', 'del', 'div', 'dfn', 'dt', 'em', 'fieldset', 'font',
		'form', 'h1', 'h2', 'h3', 'h4', 'h5', 'h6', 'i', 'iframe',
		'ins', 'kdb', 'li', 'object', 'pre', 'p', 'q', 'samp',
		'small', 'span', 'strike', 's', 'strong', 'sub', 'sup',
		'td', 'th', 'tt', 'u', 'var'];

	var xpath = '//text( )[(parent::' + allowedParents.join(' or parent::') +
		')]';

	var candidates = document.evaluate(xpath, document, null,
		XPathResult.UNORDERED_NODE_SNAPSHOT_TYPE, null);

	//var tO = new Date( ).getTime( );
	for (var cand = null, i = 0; (cand = candidates.snapshotItem(i)); i++) {

	// UPS Track
	if (UPSRegex.test(cand.nodeValue)) {
		var span = document.createElement('span');
		var source = cand.nodeValue;

		cand.parentNode.replaceChild(span, cand);
	
		UPSRegex.lastIndex = 0;
		for (var match = null, lastLastIndex = 0;
			 (match = UPSRegex.exec(source)); ) {
			span.appendChild(document.createTextNode(
				source.substring(lastLastIndex, match.index)));

			var a = document.createElement('a');
			a.setAttribute('href', UPSUrl(match[0]));
			a.setAttribute('title', 'Linkified to UPS');
			a.appendChild(document.createTextNode(match[0]));
			span.appendChild(a);

			lastLastIndex = UPSRegex.lastIndex;
		}
		
		span.appendChild(document.createTextNode(
			source.substring(lastLastIndex)));
		span.normalize( );
	}

	// USPS Track
	if (USARegex.test(cand.nodeValue)) {
		var span = document.createElement('span');

		var source = cand.nodeValue;
		
		cand.parentNode.replaceChild(span, cand);

		USARegex.lastIndex = 0;
		for (var match = null, lastLastIndex = 0;
			 (match = USARegex.exec(source)); ) {
			span.appendChild(document.createTextNode(
				source.substring(lastLastIndex, match.index)));

			var a = document.createElement('a');
			a.setAttribute('href', USAUrl(match[0]));
			a.setAttribute('title', 'Linkified to USPS');
			a.appendChild(document.createTextNode(match[0]));
			span.appendChild(a);

			lastLastIndex = USARegex.lastIndex;
		}

		span.appendChild(document.createTextNode(
			source.substring(lastLastIndex)));
		span.normalize( );
	}

	// FedEx Track
	if (FEXRegex.test(cand.nodeValue)) {
		var span = document.createElement('span');
		var source = cand.nodeValue;

		cand.parentNode.replaceChild(span, cand);

		FEXRegex.lastIndex = 0;
		for (var match = null, lastLastIndex = 0;
			 (match = FEXRegex.exec(source)); ) {
			span.appendChild(document.createTextNode(
				source.substring(lastLastIndex, match.index)));

			var a = document.createElement('a');
			a.setAttribute('href', FEXUrl(match[0]));
			a.setAttribute('title', 'Linkified to FedEx');
			a.appendChild(document.createTextNode(match[0]));
			span.appendChild(a);

			lastLastIndex = FEXRegex.lastIndex;
		}

		span.appendChild(document.createTextNode(
			source.substring(lastLastIndex)));
		span.normalize( );
	}
  }