diff --git a/blocks/logic.js b/blocks/logic.js
index 6406f77a7..5899e04a5 100644
--- a/blocks/logic.js
+++ b/blocks/logic.js
@@ -295,8 +295,8 @@ Blockly.Constants.Logic.TOOLTIPS_BY_OP = {
 };
 
 Blockly.Extensions.register('logic_op_tooltip',
-  Blockly.Extensions.buildTooltipForDropdown(
-    'OP', Blockly.Constants.Logic.TOOLTIPS_BY_OP));
+    Blockly.Extensions.buildTooltipForDropdown(
+        'OP', Blockly.Constants.Logic.TOOLTIPS_BY_OP));
 
 /**
  * Mutator methods added to controls_if blocks.
@@ -486,7 +486,7 @@ Blockly.Constants.Logic.CONTROLS_IF_TOOLTIP_EXTENSION = function() {
 };
 
 Blockly.Extensions.register('controls_if_tooltip',
-  Blockly.Constants.Logic.CONTROLS_IF_TOOLTIP_EXTENSION);
+    Blockly.Constants.Logic.CONTROLS_IF_TOOLTIP_EXTENSION);
 
 /**
  * Corrects the logic_compare dropdown label with respect to language direction.
@@ -574,7 +574,7 @@ Blockly.Constants.Logic.LOGIC_COMPARE_EXTENSION = function() {
 };
 
 Blockly.Extensions.register('logic_compare',
-  Blockly.Constants.Logic.LOGIC_COMPARE_EXTENSION);
+    Blockly.Constants.Logic.LOGIC_COMPARE_EXTENSION);
 
 /**
  * Adds type coordination between inputs and output.
@@ -619,4 +619,4 @@ Blockly.Constants.Logic.LOGIC_TERNARY_ONCHANGE_MIXIN = {
 };
 
 Blockly.Extensions.registerMixin('logic_ternary',
-  Blockly.Constants.Logic.LOGIC_TERNARY_ONCHANGE_MIXIN);
+    Blockly.Constants.Logic.LOGIC_TERNARY_ONCHANGE_MIXIN);
diff --git a/blocks/loops.js b/blocks/loops.js
index 7000636ec..24321bfec 100644
--- a/blocks/loops.js
+++ b/blocks/loops.js
@@ -227,8 +227,8 @@ Blockly.Constants.Loops.WHILE_UNTIL_TOOLTIPS = {
 };
 
 Blockly.Extensions.register('controls_whileUntil_tooltip',
-  Blockly.Extensions.buildTooltipForDropdown(
-    'MODE', Blockly.Constants.Loops.WHILE_UNTIL_TOOLTIPS));
+    Blockly.Extensions.buildTooltipForDropdown(
+      'MODE', Blockly.Constants.Loops.WHILE_UNTIL_TOOLTIPS));
 
 /**
  * Tooltips for the 'controls_flow_statements' block, keyed by FLOW value.
@@ -242,8 +242,8 @@ Blockly.Constants.Loops.BREAK_CONTINUE_TOOLTIPS = {
 };
 
 Blockly.Extensions.register('controls_flow_tooltip',
-  Blockly.Extensions.buildTooltipForDropdown(
-    'FLOW', Blockly.Constants.Loops.BREAK_CONTINUE_TOOLTIPS));
+    Blockly.Extensions.buildTooltipForDropdown(
+      'FLOW', Blockly.Constants.Loops.BREAK_CONTINUE_TOOLTIPS));
 
 /**
  * Mixin to add a context menu item to create a 'variables_get' block.
@@ -277,15 +277,15 @@ Blockly.Constants.Loops.CUSTOM_CONTEXT_MENU_CREATE_VARIABLES_GET_MIXIN = {
 };
 
 Blockly.Extensions.registerMixin('contextMenu_newGetVariableBlock',
-  Blockly.Constants.Loops.CUSTOM_CONTEXT_MENU_CREATE_VARIABLES_GET_MIXIN);
+    Blockly.Constants.Loops.CUSTOM_CONTEXT_MENU_CREATE_VARIABLES_GET_MIXIN);
 
 Blockly.Extensions.register('controls_for_tooltip',
-  Blockly.Extensions.buildTooltipWithFieldValue(
-    Blockly.Msg.CONTROLS_FOR_TOOLTIP, 'VAR'));
+    Blockly.Extensions.buildTooltipWithFieldValue(
+        Blockly.Msg.CONTROLS_FOR_TOOLTIP, 'VAR'));
 
 Blockly.Extensions.register('controls_forEach_tooltip',
-  Blockly.Extensions.buildTooltipWithFieldValue(
-    Blockly.Msg.CONTROLS_FOREACH_TOOLTIP, 'VAR'));
+    Blockly.Extensions.buildTooltipWithFieldValue(
+        Blockly.Msg.CONTROLS_FOREACH_TOOLTIP, 'VAR'));
 
 /**
  * This mixin adds a check to make sure the 'controls_flow_statements' block
@@ -339,4 +339,4 @@ Blockly.Constants.Loops.CONTROL_FLOW_CHECK_IN_LOOP_MIXIN = {
 };
 
 Blockly.Extensions.registerMixin('controls_flow_in_loop_check',
-  Blockly.Constants.Loops.CONTROL_FLOW_IN_LOOP_CHECK_MIXIN);
+    Blockly.Constants.Loops.CONTROL_FLOW_IN_LOOP_CHECK_MIXIN);
diff --git a/blocks/math.js b/blocks/math.js
index ca04dc728..8244618f9 100644
--- a/blocks/math.js
+++ b/blocks/math.js
@@ -422,8 +422,8 @@ Blockly.Constants.Math.TOOLTIPS_BY_OP = {
 };
 
 Blockly.Extensions.register('math_op_tooltip',
-  Blockly.Extensions.buildTooltipForDropdown(
-    'OP', Blockly.Constants.Math.TOOLTIPS_BY_OP));
+    Blockly.Extensions.buildTooltipForDropdown(
+        'OP', Blockly.Constants.Math.TOOLTIPS_BY_OP));
 
 
 /**
@@ -489,8 +489,8 @@ Blockly.Constants.Math.IS_DIVISIBLE_MUTATOR_EXTENSION = function() {
 };
 
 Blockly.Extensions.registerMutator('math_is_divisibleby_mutator',
-  Blockly.Constants.Math.IS_DIVISIBLEBY_MUTATOR_MIXIN,
-  Blockly.Constants.Math.IS_DIVISIBLE_MUTATOR_EXTENSION);
+    Blockly.Constants.Math.IS_DIVISIBLEBY_MUTATOR_MIXIN,
+    Blockly.Constants.Math.IS_DIVISIBLE_MUTATOR_EXTENSION);
 
 /**
  * Update the tooltip of 'math_change' block to reference the variable.
@@ -505,8 +505,8 @@ Blockly.Constants.Math.CHANGE_TOOLTIP_EXTENSION = function() {
 };
 
 Blockly.Extensions.register('math_change_tooltip',
-  Blockly.Extensions.buildTooltipWithFieldValue(
-    Blockly.Msg.MATH_CHANGE_TOOLTIP, 'VAR'));
+    Blockly.Extensions.buildTooltipWithFieldValue(
+        Blockly.Msg.MATH_CHANGE_TOOLTIP, 'VAR'));
 
 /**
  * Mixin with mutator methods to support alternate output based if the
@@ -563,5 +563,5 @@ Blockly.Constants.Math.LIST_MODES_MUTATOR_EXTENSION = function() {
 };
 
 Blockly.Extensions.registerMutator('math_modes_of_list_mutator',
-  Blockly.Constants.Math.LIST_MODES_MUTATOR_MIXIN,
-  Blockly.Constants.Math.LIST_MODES_MUTATOR_EXTENSION);
+    Blockly.Constants.Math.LIST_MODES_MUTATOR_MIXIN,
+    Blockly.Constants.Math.LIST_MODES_MUTATOR_EXTENSION);
diff --git a/blocks/text.js b/blocks/text.js
index 22dda35e8..3e0d62de9 100644
--- a/blocks/text.js
+++ b/blocks/text.js
@@ -876,18 +876,18 @@ Blockly.Constants.Text.TEXT_CHARAT_EXTENSION = function() {
 };
 
 Blockly.Extensions.register('text_indexOf_tooltip',
-  Blockly.Constants.Text.TEXT_INDEXOF_TOOLTIP_EXTENSION);
+    Blockly.Constants.Text.TEXT_INDEXOF_TOOLTIP_EXTENSION);
 
 Blockly.Extensions.register('text_quotes',
-  Blockly.Constants.Text.TEXT_QUOTES_EXTENSION);
+    Blockly.Constants.Text.TEXT_QUOTES_EXTENSION);
 
 Blockly.Extensions.register('text_append_tooltip',
-  Blockly.Constants.Text.TEXT_APPEND_TOOLTIP_EXTENSION);
+    Blockly.Constants.Text.TEXT_APPEND_TOOLTIP_EXTENSION);
 
 Blockly.Extensions.registerMutator('text_join_mutator',
-  Blockly.Constants.Text.TEXT_JOIN_MUTATOR_MIXIN,
-  Blockly.Constants.Text.TEXT_JOIN_EXTENSION);
+    Blockly.Constants.Text.TEXT_JOIN_MUTATOR_MIXIN,
+    Blockly.Constants.Text.TEXT_JOIN_EXTENSION);
 
 Blockly.Extensions.registerMutator('text_charAt_mutator',
-  Blockly.Constants.Text.TEXT_CHARAT_MUTATOR_MIXIN,
-  Blockly.Constants.Text.TEXT_CHARAT_EXTENSION);
\ No newline at end of file
+    Blockly.Constants.Text.TEXT_CHARAT_MUTATOR_MIXIN,
+    Blockly.Constants.Text.TEXT_CHARAT_EXTENSION);
diff --git a/core/extensions.js b/core/extensions.js
index 607ef0271..2ec647caa 100644
--- a/core/extensions.js
+++ b/core/extensions.js
@@ -83,14 +83,14 @@ Blockly.Extensions.registerMixin = function(name, mixinObj) {
  * decompose are defined on the mixin.
  * @param {string} name The name of this mutator extension.
  * @param {!Object} mixinObj The values to mix in.
- * @param {(function())=} opt_helperFn An optional function to apply after mixing
- *     in the object.
+ * @param {(function())=} opt_helperFn An optional function to apply after
+ *     mixing in the object.
  * @param {Array.<string>=} opt_blockList A list of blocks to appear in the
  *     flyout of the mutator dialog.
  * @throws {Error} if the mutation is invalid or can't be applied to the block.
  */
-Blockly.Extensions.registerMutator = function(name, mixinObj, opt_helperFn,
-    opt_blockList) {
+Blockly.Extensions.registerMutator =
+    function(name, mixinObj, opt_helperFn, opt_blockList) {
   var errorPrefix = 'Error when registering mutator "' + name + '": ';
 
   // Sanity check the mixin object before registering it.
@@ -99,8 +99,8 @@ Blockly.Extensions.registerMutator = function(name, mixinObj, opt_helperFn,
   Blockly.Extensions.checkHasFunction_(errorPrefix, mixinObj.mutationToDom,
                                        'mutationToDom');
 
-  var hasMutatorDialog = Blockly.Extensions.checkMutatorDialog_(mixinObj,
-    errorPrefix);
+  var hasMutatorDialog =
+      Blockly.Extensions.checkMutatorDialog_(mixinObj, errorPrefix);
 
   if (opt_helperFn && !goog.isFunction(opt_helperFn)) {
     throw new Error('Extension "' + name + '" is not a function');
@@ -148,8 +148,8 @@ Blockly.Extensions.apply = function(name, block, isMutator) {
     Blockly.Extensions.checkBlockHasMutatorProperties_(errorPrefix, block);
   } else {
     if (!Blockly.Extensions.mutatorPropertiesMatch_(mutatorProperties, block)) {
-      throw new Error('Error when applying extension "' + name +
-          '": mutation properties changed when applying a non-mutator extension.');
+      throw new Error('Error when applying extension "' + name + '": ' +
+          'mutation properties changed when applying a non-mutator extension.');
     }
   }
 };
@@ -162,14 +162,14 @@ Blockly.Extensions.apply = function(name, block, isMutator) {
  * @throws {Error} if the property does not exist or is not a function.
  * @private
  */
-Blockly.Extensions.checkHasFunction_ = function(errorPrefix, func,
-    propertyName) {
+Blockly.Extensions.checkHasFunction_ =
+    function(errorPrefix, func, propertyName) {
   if (!func) {
     throw new Error(errorPrefix +
         'missing required property "' + propertyName + '"');
   } else if (typeof func != 'function') {
     throw new Error(errorPrefix +
-      '" required property "' + propertyName + '" must be a function');
+        '" required property "' + propertyName + '" must be a function');
   }
 };
 
@@ -209,9 +209,9 @@ Blockly.Extensions.checkMutatorDialog_ = function(object, errorPrefix) {
   var hasDecompose = object.decompose !== undefined;
 
   if (hasCompose && hasDecompose) {
-    if (typeof object.compose !== 'function') {
+    if (typeof object.compose != 'function') {
       throw new Error(errorPrefix + 'compose must be a function.');
-    } else if (typeof object.decompose !== 'function') {
+    } else if (typeof object.decompose != 'function') {
       throw new Error(errorPrefix + 'decompose must be a function.');
     }
     return true;
@@ -230,13 +230,15 @@ Blockly.Extensions.checkMutatorDialog_ = function(object, errorPrefix) {
  * @param {!Blockly.Block} block The block to inspect.
  * @private
  */
-Blockly.Extensions.checkBlockHasMutatorProperties_ = function(errorPrefix,
-    block) {
-  if (typeof block.domToMutation !== 'function') {
-    throw new Error(errorPrefix + 'Applying a mutator didn\'t add "domToMutation"');
+Blockly.Extensions.checkBlockHasMutatorProperties_ =
+    function(errorPrefix, block) {
+  if (typeof block.domToMutation != 'function') {
+    throw new Error(errorPrefix +
+                    'Applying a mutator didn\'t add "domToMutation"');
   }
-  if (typeof block.mutationToDom !== 'function') {
-    throw new Error(errorPrefix + 'Applying a mutator didn\'t add "mutationToDom"');
+  if (typeof block.mutationToDom != 'function') {
+    throw new Error(errorPrefix +
+                    'Applying a mutator didn\'t add "mutationToDom"');
   }
 
   // A block with a mutator isn't required to have a mutation dialog, but
@@ -280,19 +282,16 @@ Blockly.Extensions.getMutatorProperties_ = function(block) {
  * @private
  */
 Blockly.Extensions.mutatorPropertiesMatch_ = function(oldProperties, block) {
-  var match = true;
   var newProperties = Blockly.Extensions.getMutatorProperties_(block);
   if (newProperties.length != oldProperties.length) {
-    match = false;
-  } else {
-    for (var i = 0; i < newProperties.length; i++) {
-      if (oldProperties[i] != newProperties[i]) {
-        match = false;
-      }
+    return false;
+  }
+  for (var i = 0; i < newProperties.length; i++) {
+    if (oldProperties[i] != newProperties[i]) {
+      return false;
     }
   }
-
-  return match;
+  return true;
 };
 
 /**
@@ -314,7 +313,8 @@ Blockly.Extensions.mutatorPropertiesMatch_ = function(oldProperties, block) {
  *     tooltip text.
  * @return {Function} The extension function.
  */
-Blockly.Extensions.buildTooltipForDropdown = function(dropdownName, lookupTable) {
+Blockly.Extensions.buildTooltipForDropdown =
+    function(dropdownName, lookupTable) {
   // List of block types already validated, to minimize duplicate warnings.
   var blockTypesChecked = [];
 
@@ -338,7 +338,7 @@ Blockly.Extensions.buildTooltipForDropdown = function(dropdownName, lookupTable)
   var extensionFn = function() {
     if (this.type && blockTypesChecked.indexOf(this.type) === -1) {
       Blockly.Extensions.checkDropdownOptionsInTable_(
-        this, dropdownName, lookupTable);
+          this, dropdownName, lookupTable);
       blockTypesChecked.push(this.type);
     }
 
@@ -347,7 +347,7 @@ Blockly.Extensions.buildTooltipForDropdown = function(dropdownName, lookupTable)
       var tooltip = lookupTable[value];
       if (tooltip == null) {
         if (blockTypesChecked.indexOf(this.type) === -1) {
-          // Warn for missing values on generated tooltips
+          // Warn for missing values on generated tooltips.
           var warning = 'No tooltip mapping for value ' + value +
               ' of field ' + dropdownName;
           if (this.type != null) {
@@ -373,20 +373,20 @@ Blockly.Extensions.buildTooltipForDropdown = function(dropdownName, lookupTable)
  * @private
  */
 Blockly.Extensions.checkDropdownOptionsInTable_ =
-  function(block, dropdownName, lookupTable) {
-    // Validate all dropdown options have values.
-    var dropdown = block.getField(dropdownName);
-    if (!dropdown.isOptionListDynamic()) {
-      var options = dropdown.getOptions();
-      for (var i = 0; i < options.length; ++i) {
-        var optionKey = options[i][1]; // label, then value
-        if (lookupTable[optionKey] == null) {
-          console.warn('No tooltip mapping for value ' + optionKey +
-            ' of field ' + dropdownName + ' of block type ' + block.type);
-        }
+    function(block, dropdownName, lookupTable) {
+  // Validate all dropdown options have values.
+  var dropdown = block.getField(dropdownName);
+  if (!dropdown.isOptionListDynamic()) {
+    var options = dropdown.getOptions();
+    for (var i = 0; i < options.length; ++i) {
+      var optionKey = options[i][1];  // label, then value
+      if (lookupTable[optionKey] == null) {
+        console.warn('No tooltip mapping for value ' + optionKey +
+          ' of field ' + dropdownName + ' of block type ' + block.type);
       }
     }
-  };
+  }
+};
 
 /**
  * Builds an extension function that will install a dynamic tooltip. The
@@ -398,30 +398,30 @@ Blockly.Extensions.checkDropdownOptionsInTable_ =
  * @returns {Function} The extension function.
  */
 Blockly.Extensions.buildTooltipWithFieldValue =
-  function(msgTemplate, fieldName) {
-    // Check the tooltip string messages for invalid references.
-    // Wait for load, in case Blockly.Msg is not yet populated.
-    // runAfterPageLoad() does not run in a Node.js environment due to lack of
-    // document object, in which case skip the validation.
-    if (document) { // Relies on document.readyState
-      Blockly.utils.runAfterPageLoad(function() {
-        // Will print warnings is reference is missing.
-        Blockly.utils.checkMessageReferences(msgTemplate);
-      });
-    }
+    function(msgTemplate, fieldName) {
+  // Check the tooltip string messages for invalid references.
+  // Wait for load, in case Blockly.Msg is not yet populated.
+  // runAfterPageLoad() does not run in a Node.js environment due to lack of
+  // document object, in which case skip the validation.
+  if (document) {  // Relies on document.readyState
+    Blockly.utils.runAfterPageLoad(function() {
+      // Will print warnings is reference is missing.
+      Blockly.utils.checkMessageReferences(msgTemplate);
+    });
+  }
 
-    /**
-     * The actual extension.
-     * @this {Blockly.Block}
-     */
-    var extensionFn = function() {
-      this.setTooltip(function() {
-        return Blockly.utils.replaceMessageReferences(msgTemplate)
-            .replace('%1', this.getFieldValue(fieldName));
-      }.bind(this));
-    };
-    return extensionFn;
+  /**
+   * The actual extension.
+   * @this {Blockly.Block}
+   */
+  var extensionFn = function() {
+    this.setTooltip(function() {
+      return Blockly.utils.replaceMessageReferences(msgTemplate)
+          .replace('%1', this.getFieldValue(fieldName));
+    }.bind(this));
   };
+  return extensionFn;
+};
 
 /**
  * Configures the tooltip to mimic the parent block when connected. Otherwise,
@@ -435,10 +435,8 @@ Blockly.Extensions.extensionParentTooltip_ = function() {
   this.tooltipWhenNotConnected_ = this.tooltip;
   this.setTooltip(function() {
     var parent = this.getParent();
-    return (parent &&
-      parent.getInputsInline() &&
-      parent.tooltip) ||
-      this.tooltipWhenNotConnected_;
+    return (parent && parent.getInputsInline() && parent.tooltip) ||
+        this.tooltipWhenNotConnected_;
   }.bind(this));
 };
 Blockly.Extensions.register('parent_tooltip_when_inline',
diff --git a/core/field_image.js b/core/field_image.js
index 3960169a4..e9767f9c9 100644
--- a/core/field_image.js
+++ b/core/field_image.js
@@ -54,7 +54,7 @@ Blockly.FieldImage = function(src, width, height, opt_alt, opt_onClick) {
   this.text_ = opt_alt || '';
   this.setValue(src);
 
-  if (typeof opt_onClick === "function") {
+  if (typeof opt_onClick == 'function') {
     this.clickHandler_ = opt_onClick;
   }
 };
diff --git a/core/utils.js b/core/utils.js
index 62c150ea3..7b0a05a50 100644
--- a/core/utils.js
+++ b/core/utils.js
@@ -44,7 +44,7 @@ goog.require('goog.userAgent');
  * is not possible. To access the exported Blockly.Msg.Something it needs to be
  * accessed through the exact name that was exported. Note, that all the exports
  * are happening as the last thing in the generated js files, so they won't be
- * accessible before javascript loads!
+ * accessible before JavaScript loads!
  * @return {!Object<string, string>}
  * @private
  */
@@ -208,10 +208,9 @@ Blockly.utils.getRelativeXY = function(element) {
 Blockly.utils.getInjectionDivXY_ = function(element) {
   var x = 0;
   var y = 0;
-  var scale = 1;
   while (element) {
     var xy = Blockly.utils.getRelativeXY(element);
-    scale = Blockly.utils.getScale_(element);
+    var scale = Blockly.utils.getScale_(element);
     x = (x * scale) + xy.x;
     y = (y * scale) + xy.y;
     var classes = element.getAttribute('class') || '';
@@ -465,18 +464,18 @@ Blockly.utils.replaceMessageReferences = function(message) {
  *     Otherwise, false.
  */
 Blockly.utils.checkMessageReferences = function(message) {
-  var isValid = true; // True until a bad reference is found
+  var isValid = true;  // True until a bad reference is found.
 
   var regex = /%{BKY_([a-zA-Z][a-zA-Z0-9_]*)}/g;
   var match = regex.exec(message);
-  while (match != null) {
+  while (match) {
     var msgKey = match[1];
-    if (Blockly.utils.getMessageArray_()[msgKey] == null) {
+    if (Blockly.utils.getMessageArray_()[msgKey] == undefined) {
       console.log('WARNING: No message string for %{BKY_' + msgKey + '}.');
       isValid = false;
     }
 
-    // Re-run on remainder of sting.
+    // Re-run on remainder of string.
     message = message.substring(match.index + msgKey.length + 1);
     match = regex.exec(message);
   }
@@ -485,7 +484,7 @@ Blockly.utils.checkMessageReferences = function(message) {
 };
 
 /**
- * Internal implemention of the message reference and interpolation token
+ * Internal implementation of the message reference and interpolation token
  * parsing used by tokenizeInterpolation() and replaceMessageReferences().
  * @param {string} message Text which might contain string table references and
  *     interpolation tokens.
@@ -494,7 +493,8 @@ Blockly.utils.checkMessageReferences = function(message) {
  * @return {!Array.<string|number>} Array of strings and numbers.
  * @private
  */
-Blockly.utils.tokenizeInterpolation_ = function(message, parseInterpolationTokens) {
+Blockly.utils.tokenizeInterpolation_ =
+    function(message, parseInterpolationTokens) {
   var tokens = [];
   var chars = message.split('');
   chars.push('');  // End marker.
@@ -640,7 +640,7 @@ Blockly.utils.genUid = function() {
  * Legal characters for the unique ID.  Should be all on a US keyboard.
  * No characters that conflict with XML or JSON.  Requests to remove additional
  * 'problematic' characters from this soup will be denied.  That's your failure
- * to properly escape in your own environment.  Issues #251, #625, #682.
+ * to properly escape in your own environment.  Issues #251, #625, #682, #1304.
  * @private
  */
 Blockly.utils.genUid.soup_ = '!#$%()*+,-./:;=?@[]^_`{|}~' +
@@ -937,4 +937,3 @@ Blockly.utils.getViewportBBox = function() {
     left: scrollOffset.x
   };
 };
-