Current Web technologies allow developers to create rich Web-applications. Unlike desktop applications Web 2.0 programs are cre- ated by easily linking several existing components. This approach, also known as mashup, allows to use JavaScript to connect web-services and browser components together. I have extended this development method by bringing 3D and virtual world networking components into the browser. This allowed me to create Virtual Worlds Web-application similar to Second Life. I have wrapped the open-source Sirikata platform for virtual worlds into a Web-service com- ponent, created XML3D rendering component, combined them with other browser services and thus created a fully-featured 3D world application right inside of the browser.