Janvas is a great example that an online tool has little to envy to a desktop program.
Janvas works as an application for Chrome, so you'll need this browser to use it.
In addition to vector graphics in PNG and SVG, it supports content in HTML, CSS and Javascript to integrate into web pages. All the generated content is downloadable or you can save it in your Google Drive space, and if you do not know how to start working with Janvas, you have a list of video tutorials to familiarize yourself with its interface.