My first grease monkey script

I wrote my first grease monkey script today. It is to apply a XSLT style sheet on certain types of XML files. This is because usually the xml contains too much information and I just want ot view certain part of it and in more clean format such as a table. Here is the code:

/*
Title:
xml transformer

Description:
This is a Greasemonkey user script for Firefox.

This script applies XSLT on plain XML files
*/

// ==UserScript==
// @name xml transformer
// @namespace http://sample.com
// @description apply XSLT on plain XML
// @include http://localhost/*.xml
// ==/UserScript==

var contentType = 'text/html';
detectFormats();

function detectFormats() {
 // define classNames and URLs of corresponding XSLT files - edit this to add new formats
 var b = new Array();
 b[0] = new Array('Root1', 'http://localhost/gmonkey/xslt/root1.xslt', 'text/html');
 b[1] = new Array('Root2', 'http://localhost/gmonkey/xslt/root2.xslt', 'text/html');

 // look for certain signature in document
 for (i=0; i<b.len; i++) {
  var schemaType = b[i][0];
  if (document.getElementsByTagName(schemaType).length > 0){
   xsltURL = b[i][1];
   contentType = b[i][2];
   GM_log(xsltURL);
   fetchXSLT(xsltURL);
  }
 }
}

function fetchXSLT(url){
 GM_xmlhttpRequest({
  method: "GET",
  url: url,
  headers: {
   'User-agent': 'Mozilla/4.0 (compatible) Greasemonkey',
   'Accept': 'application/atom+xml,application/xml,text/xml',
   'Cache-Control': 'no-cache',
  },
  onload: function(response) {
   var xslt = new DOMParser().parseFromString(response.responseText, "text/xml");
   transformXML(xslt);
  }
 });
}

// transform the document to RDF using the XSLT file
function transformXML(xslt){
 var processor = new XSLTProcessor();
 processor.importStylesheet(xslt);
 var dataXML = document;
 var processed = processor.transformToDocument(dataXML);
 var dataString = (new XMLSerializer()).serializeToString(processed);
 location.href = 'data:' + contentType + ',' + dataString;
}