it will highlight a tags you clicked.
// ==UserScript==
// @name Highlight Clicked button
// @namespace http://tampermonkey.net/sftec
// @version 0.3
// @description it will highlight a tags you clicked.
// @author sftec
// @match *://*/*
// ==/UserScript==
(function() {
var style = document.createElement("style");
style.type = "text/css";
var text = document.createTextNode("a:visited,a:active,a:hover{color:#800000!important;}");
style.appendChild(text);
var head = document.getElementsByTagName("head")[0];
head.appendChild(style);
})();