Accessing a WebGL context
A WebGL context is a handle (more strictly a JavaScript object) through which we can access all the WebGL functions and attributes. These constitute WebGL's Application Program Interface (API).
We are going to create a JavaScript function that will check whether a WebGL context can be obtained for the canvas or not. Unlike other JavaScript libraries that need to be downloaded and included in your projects to work, WebGL is already in your browser. In other words, if you are using one of the supported browsers, you don't need to install or include any library.