data:image/svg+xml,<svg xmlns="http://www.w3.org/2000/svg"> <rect x="20" y="20" width="100" height="50" fill="red"/></svg>into the address bar of your browser. This works in Firefox, Opera, and Chrome. I haven’t checked IE.
During a recent SVG Working Group meeting a question arose about current browser support for a particular SVG syntax. One of the group members pasted a quick one-line test case into the IRC meeting log and we were able to verify browser support by just pasting the line into the address bar. Try pasting: