Initial element hiding functionality

includes/cssFilter.js

-// ==UserScript==
-// @include *
-// ==/UserScript== 
-
-opera.extension.onmessage = function (event) {
-        //opera.postError('INJECTED: got a ' + event.data.request + ' request for ' + document.location.href);
-        if(event.data.request == 'css') {//Ensure the received message is for the right URL
-                var css = document.getElementById(event.data.id);
-                if(!css) {
-                        css = document.createElement('style');
-                        css.setAttribute('type', 'text/css');
-                        css.setAttribute('id', event.data.id);
-                        css.setAttribute('class', 'OAB'); //To allow easy removal by the user to view the original source code
-                        css.appendChild(document.createTextNode(event.data.reply));
-                        try {
-                                document.getElementsByTagName('html')[0].getElementsByTagName('head')[0].appendChild(css); //Only append if the file is an HTML file
-                                //opera.postError('INJECTED: CSS added - ' + event.data.id);
-                        }
-                        catch(e) {}
-                }
-                else {
-                        css.innerHTML = event.data.reply;
-                        //opera.postError('INJECTED: CSS updated - ' + event.data.id);
-                }
-        }
-        else if(event.data.request == 'ping') {
-                if(event.data.type == 'css')
-                        event.source.postMessage({request: 'css', url: document.location.href});
-        }
-};
-
-opera.extension.postMessage({request: 'css', url: document.location.href});