diff --git a/src/ol/renderer/webgl/webglmaprenderer.js b/src/ol/renderer/webgl/webglmaprenderer.js
index 1d44b1e0c8..52a025120a 100644
--- a/src/ol/renderer/webgl/webglmaprenderer.js
+++ b/src/ol/renderer/webgl/webglmaprenderer.js
@@ -526,8 +526,8 @@ ol.renderer.webgl.Map.prototype.renderFrame = function(frameState) {
 
   var layerStates = frameState.layerStates;
   var layersArray = frameState.layersArray;
-  var i, layer, layerRenderer, layerState;
-  for (i = 0; i < layersArray.length; ++i) {
+  var i, ii, layer, layerRenderer, layerState;
+  for (i = 0, ii = layersArray.length; i < ii; ++i) {
     layer = layersArray[i];
     layerRenderer = this.getLayerRenderer(layer);
     layerState = frameState.layerStates[goog.getUid(layer)];
@@ -556,7 +556,7 @@ ol.renderer.webgl.Map.prototype.renderFrame = function(frameState) {
 
   var currentProgram = null;
   var locations;
-  for (i = 0; i < layersArray.length; ++i) {
+  for (i = 0, ii = layersArray.length; i < ii; ++i) {
 
     layer = layersArray[i];
     layerState = frameState.layerStates[goog.getUid(layer)];
diff --git a/src/ol/renderer/webgl/webgltilelayerrenderer.js b/src/ol/renderer/webgl/webgltilelayerrenderer.js
index 4adf2f936b..115df49571 100644
--- a/src/ol/renderer/webgl/webgltilelayerrenderer.js
+++ b/src/ol/renderer/webgl/webgltilelayerrenderer.js
@@ -233,8 +233,8 @@ ol.renderer.webgl.TileLayer.prototype.renderFrame =
     var zs = goog.array.map(goog.object.getKeys(tilesToDrawByZ), Number);
     goog.array.sort(zs);
     var u_tileOffset = goog.vec.Vec4.createFloat32();
-    var i, sx, sy, tileExtent, tileKey, tilesToDraw, tx, ty;
-    for (i = 0; i < zs.length; ++i) {
+    var i, ii, sx, sy, tileExtent, tileKey, tilesToDraw, tx, ty;
+    for (i = 0, ii = zs.length; i < ii; ++i) {
       tilesToDraw = tilesToDrawByZ[zs[i]];
       for (tileKey in tilesToDraw) {
         tile = tilesToDraw[tileKey];