// ==UserScript==
// @name		  Linkify
// @version        0.1
// @namespace	  http://youngpup.net/userscripts
// @description   Turn plain-text URLs into hyperlinks
// @include *
// ==/UserScript==
// based on code by Aaron Boodman
// and included here with his gracious permission
var urlRegex = /\b(https?:\/\/[^\s+\"\<\>]+)/ig;
var snapTextElements = document.evaluate("//text()[not(ancestor::a) " +
"and not(ancestor::script) and not(ancestor::style) and " +
"contains(translate(., 'HTTP', 'http'), 'http')]",
document, null, XPathR###lt.UNORDERED_NODE_SNAPSHOT_TYPE, null);
for (var i = snapTextElements.snapshotLength - 1; i >= 0; i--) {
var elmText = snapTextElements.snapshotItem(i);
if (urlRegex.test(elmText.nodeValue)) {
var elmSpan = document.createElement("span");
var sURLText = elmText.nodeValue;
elmText.parentNode.replaceChild(elmSpan, elmText);
urlRegex.lastIndex = 0;
for (var match = null, lastLastIndex = 0;
(match = urlRegex.exec(sURLText)); ) {
elmSpan.appendChild(document.createTextNode(
sURLText.substring(lastLastIndex, match.index)));
var elmLink = document.createElement("a");
elmLink.setAttribute("href", match[0]);
elmLink.appendChild(document.createTextNode(match[0]));
elmSpan.appendChild(elmLink);
lastLastIndex = urlRegex.lastIndex;
}
elmSpan.appendChild(document.createTextNode(
sURLText.substring(lastLastIndex)));
elmSpan.normalize();
}
}