Use ol.Map#getTargetElement function

src/ol/map.js

@@ -1024,13 +1024,7 @@ ol.Map.prototype.handleTargetChanged_ = function() {
   // If it's not now an Element we remove the viewport from the DOM.
   // If it's an Element we append the viewport element to it.
 
-  var target = this.getTarget();
+  var targetElement = this.getTargetElement();
-
-  /**
-   * @type {Element}
-   */
-  var targetElement = goog.isDef(target) ?
-      goog.dom.getElement(target) : null;
 
   this.keyHandler_.detach();
 
@@ -1431,12 +1425,7 @@ ol.Map.prototype.skipFeature = function(feature) {
  * @api stable
  */
 ol.Map.prototype.updateSize = function() {
-  var target = this.getTarget();
+  var targetElement = this.getTargetElement();
-
-  /**
-   * @type {Element}
-   */
-  var targetElement = goog.isDef(target) ? goog.dom.getElement(target) : null;
 
   if (goog.isNull(targetElement)) {
     this.setSize(undefined);