noVNC

"noVNC is a HTML5 VNC client that runs well in any modern browser including mobile browsers (iOS and Android).

The features include:

• Supports all modern browsers including mobile (iOS, Android)
• Supported VNC encodings: raw, copyrect, rre, hextile, tight, tightPNG
• WebSocket SSL/TLS encryption (i.e. "wss://") support
• 24-bit true color and 8 bit colour mapped
• Supports desktop resize notification/pseudo-encoding
• Local or remote cursor
• Clipboard copy/paste
• Clipping or scolling modes for large remote screens
• Easy site integration and theming (3 example themes included)
• Licensed under the MPL 2.0

Unless you are using a VNC server with support for WebSockets connections (such as x11vnc/libvncserver, QEMU, or MobileVNC), you need to use a WebSockets to TCP socket proxy. There is a python proxy included ('websockify').

https://github.com/novnc/noVNC