This is an experimental technology
Because this technology's specification has not stabilized, check the compatibility table for usage in various browsers. Also note that the syntax and behavior of an experimental technology is subject to change in future versions of browsers as the specification changes.

The WebGL2RenderingContext.waitSync() method of the WebGL 2 API returns immediately, but waits on the GL server until the given WebGLSync object is signaled.

The method is a no-op in the absence of the possibility of synchronizing between multiple GL contexts.


void gl.waitSync(sync, flags, timeout);


A WebGLSync object on which to wait on.
A GLbitfield specifying a bitwise combination of flags controlling the flushing behavior. Must be 0 (exists for extensions only).
A GLint64 specifying a timeout the server should wait before continuing. Must be gl.TIMEOUT_IGNORED.

Return value



var sync = gl.fenceSync(gl.SYNC_GPU_COMMANDS_COMPLETE, 0);
gl.waitSync(sync, 0, gl.TIMEOUT_IGNORED);


Specification Status Comment
WebGL 2.0
The definition of 'waitSync' in that specification.
Editor's Draft Initial definition for WebGL.
OpenGL ES 3.0
The definition of 'glWaitSync' in that specification.
Standard Man page of the (similar) OpenGL API.

Browser compatibility

Feature Chrome Firefox (Gecko) Internet Explorer Opera Safari
Basic support No support [2] Nightly build [1] No support No support No support
Feature Android Chrome for Android Firefox Mobile (Gecko) IE Mobile Opera Mobile Safari Mobile
Basic support No support No support No support No support No support No support

[1] WebGL 2 is enabled by default in Firefox Nightly. To enable it in a release version of Firefox, set the preference webgl.enable-prototype-webgl2 to true in about:config.

[2] To use an experimental implementation of WebGL 2 in Chrome, you have to start Chrome with the runtime flag --enable-unsafe-es3-apis.

See also

Document Tags and Contributors

 Contributors to this page: fscholz
 Last updated by: fscholz,