Acquired Opera AdBlock code

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});