The WebGLRenderingContext.bindFramebuffer() method of the WebGL API binds to the specified target the provided WebGLFramebuffer, or, if the framebuffer argument is null, the default WebGLFramebuffer, which is associated with the canvas rendering context.
bindFramebuffer(target, framebuffer)
A gl.INVALID_ENUM error is thrown if target is not gl.FRAMEBUFFER, gl.DRAW_FRAMEBUFFER, or gl.READ_FRAMEBUFFER.
const canvas = document.getElementById("canvas");
const gl = canvas.getContext("webgl");
const framebuffer = gl.createFramebuffer();
gl.bindFramebuffer(gl.FRAMEBUFFER, framebuffer);
To check the current frame buffer binding, query the FRAMEBUFFER_BINDING constant.
gl.getParameter(gl.FRAMEBUFFER_BINDING);