Implement fullscreen

Author: k00lagin

raylib.js

@@ -60,7 +60,7 @@ class RaylibJs {
             return;
         }
 
-        const canvas = document.getElementById(canvasId);
+        let canvas = document.getElementById(canvasId);
         this.ctx = canvas.getContext("2d");
         if (this.ctx === null) {
             throw new Error("Could not create 2d canvas context");
@@ -117,6 +117,18 @@ class RaylibJs {
         return false;
     }
 
+    IsWindowFullscreen() {
+        return document.fullscreenElement && document.fullscreenElement === this.ctx.canvas;
+    }
+
+    ToggleFullscreen() {
+        if (this.IsWindowFullscreen()) {
+            document.exitFullscreen()
+        } else {
+            this.ctx.canvas.requestFullscreen();
+        }
+    }
+
     SetTargetFPS(fps) {
         console.log(`The game wants to run at ${fps} FPS, but in Web we gonna just ignore it.`);
         this.targetFPS = fps;