Cleanup references to dom elements.

src/canvas.js

@@ -1258,7 +1258,7 @@ var CanvasGraphics = (function CanvasGraphicsClosure() {
   return CanvasGraphics;
 })();
 
-if (!isWorker) {
+function checkPutBinaryImageDataCompatibility() {
   // Feature detection if the browser can use an Uint8Array directly as imgData.
   var canvas = document.createElement('canvas');
   canvas.width = 1;
@@ -1293,3 +1293,6 @@ if (!isWorker) {
       };
   }
 }
+if (!isWorker) {
+  checkPutBinaryImageDataCompatibility();
+}

web/viewer.js

@@ -1707,6 +1707,7 @@ var TextLayerBuilder = function textLayerBuilder(textLayerDiv) {
       if (textDivs.length === 0) {
         clearInterval(renderTimer);
         renderingDone = true;
+        self.textLayerDiv = textLayerDiv = canvas = ctx = null;
         return;
       }
       var textDiv = textDivs.shift();