<!DOCTYPE html> <html> <head> <title>No context-fill-opacity value is provided</title> <style> img { width: 100px; height: 100px; -moz-context-properties: fill-opacity; } </style> </head> <body> <img src="data:image/svg+xml,<svg xmlns='http://www.w3.org/2000/svg'><rect width='100%' height='100%' fill='blue' fill-opacity='context-fill-opacity'/></svg>"> </body> </html>