From 6ff49fb3bfaf667fcbe17ad1eeaaeb063f221703 Mon Sep 17 00:00:00 2001
From: Neil Fraser <fraser@google.com>
Date: Fri, 16 Mar 2018 14:40:09 -0700
Subject: [PATCH] Prevent fatal errors in browsers that don't support dataset.

---
 core/block_svg.js | 4 +++-
 core/bubble.js    | 4 +++-
 2 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/core/block_svg.js b/core/block_svg.js
index 386fed093..64742b7a5 100644
--- a/core/block_svg.js
+++ b/core/block_svg.js
@@ -101,7 +101,9 @@ Blockly.BlockSvg = function(workspace, prototypeName, opt_id) {
       workspace, prototypeName, opt_id);
 
   // Expose this block's ID on its top-level SVG group.
-  this.svgGroup_.dataset.blockId = this.id;
+  if (this.svgGroup_.dataset) {
+    this.svgGroup_.dataset.id = this.id;
+  }
 };
 goog.inherits(Blockly.BlockSvg, Blockly.Block);
 
diff --git a/core/bubble.js b/core/bubble.js
index acc103f33..d1a214e6e 100644
--- a/core/bubble.js
+++ b/core/bubble.js
@@ -287,7 +287,9 @@ Blockly.Bubble.prototype.getSvgRoot = function() {
  * @param {string} id ID of block.
  */
 Blockly.Bubble.prototype.setSvgId = function(id) {
-  this.bubbleGroup_.dataset.id = id;
+  if (this.bubbleGroup_.dataset) {
+    this.bubbleGroup_.dataset.blockId = id;
+  }
 };
 
 /**