diff --git a/lib/watir/elements/element.rb b/lib/watir/elements/element.rb
index 7dc07dd9e..a6f6950fd 100644
--- a/lib/watir/elements/element.rb
+++ b/lib/watir/elements/element.rb
@@ -18,6 +18,17 @@ class Element
     attr_accessor :keyword
     attr_reader :selector
 
+    # https://www.w3.org/TR/html52/single-page.html#casesensitivity
+    CASE_INSENSITIVE_ATTRIBUTES = %i[accept accept_charset align alink axis
+                                     bgcolor charset checked clear codetype
+                                     color compact declare defer dir direction
+                                     disabled enctype face frame hreflang
+                                     http_equiv lang language link media
+                                     method multiple nohref noresize noshade
+                                     nowrap readonly rel rev rules scope
+                                     scrolling selected shape target text
+                                     type valign valuetype vlink].freeze
+
     #
     # temporarily add :id and :class_name manually since they're no longer specified in the HTML spec.
     #
diff --git a/lib/watir/locators/element/selector_builder/xpath.rb b/lib/watir/locators/element/selector_builder/xpath.rb
index 005a5d4d4..596b0a300 100644
--- a/lib/watir/locators/element/selector_builder/xpath.rb
+++ b/lib/watir/locators/element/selector_builder/xpath.rb
@@ -12,6 +12,7 @@ class XPath
 
           def build(selector)
             @selector = selector
+            @valid_attributes = build_valid_attributes
 
             @built = (@selector.keys & CAN_NOT_BUILD).each_with_object({}) do |key, hash|
               hash[key] = @selector.delete(key)
@@ -55,10 +56,7 @@ def predicate_expression(key, val)
           end
 
           def predicate_conversion(key, regexp)
-            # type attributes can be upper case - downcase them
-            # https://github.com/watir/watir/issues/72
-            downcase = key == :type || regexp.casefold?
-
+            downcase = case_insensitive_attribute?(key) || regexp.casefold?
             lhs = lhs_for(key, downcase)
 
             results = RegexpDisassembler.new(regexp).substrings
@@ -72,8 +70,10 @@ def predicate_conversion(key, regexp)
 
             add_to_matching(key, regexp, results)
 
-            results.map { |substring|
-              "contains(#{lhs}, '#{substring}')"
+            results.map { |rhs|
+              rhs = "'#{rhs}'"
+              rhs = XpathSupport.downcase(rhs) if downcase
+              "contains(#{lhs}, #{rhs})"
             }.flatten.compact.join(' and ')
           end
 
@@ -236,9 +236,34 @@ def equal_pair(key, value)
 
               negate_xpath ? "not(#{expression})" : expression
             else
-              "#{lhs_for(key, key == :type)}=#{XpathSupport.escape value}"
+              downcase = case_insensitive_attribute?(key)
+
+              lhs = lhs_for(key, downcase)
+              rhs = XpathSupport.escape(value)
+              rhs = XpathSupport.downcase(rhs) if downcase
+
+              "#{lhs}=#{rhs}"
+            end
+          end
+
+          def build_valid_attributes
+            tag_name = @selector[:tag_name]
+            if tag_name.is_a?(String) && Watir.tag_to_class[tag_name.to_sym]
+              Watir.tag_to_class[tag_name.to_sym].attribute_list
+            else
+              Watir::HTMLElement.attribute_list
             end
           end
+
+          def case_insensitive_attribute?(attribute)
+            # type attributes can be upper case - downcase them
+            # https://github.com/watir/watir/issues/72
+            return true if attribute == :type
+            return true if Watir::Element::CASE_INSENSITIVE_ATTRIBUTES.include?(attribute) &&
+                           @valid_attributes.include?(attribute)
+
+            false
+          end
         end
       end
     end
diff --git a/lib/watir/locators/text_field/selector_builder/xpath.rb b/lib/watir/locators/text_field/selector_builder/xpath.rb
index 57227db7b..600c93ecf 100644
--- a/lib/watir/locators/text_field/selector_builder/xpath.rb
+++ b/lib/watir/locators/text_field/selector_builder/xpath.rb
@@ -36,7 +36,9 @@ def type_string(type)
 
           def negative_type_text
             Watir::TextField::NON_TEXT_TYPES.map { |type|
-              "#{lhs_for(:type, true)}!=#{SelectorBuilder::XpathSupport.escape type}"
+              lhs = lhs_for(:type, true)
+              rhs = SelectorBuilder::XpathSupport.downcase(SelectorBuilder::XpathSupport.escape(type))
+              "#{lhs}!=#{rhs}"
             }.join(' and ')
           end
         end
diff --git a/spec/unit/selector_builder/button_spec.rb b/spec/unit/selector_builder/button_spec.rb
index f25b70ef6..b41457d7f 100644
--- a/spec/unit/selector_builder/button_spec.rb
+++ b/spec/unit/selector_builder/button_spec.rb
@@ -7,10 +7,10 @@
   let(:uppercase) { 'ABCDEFGHIJKLMNOPQRSTUVWXYZÀÁÂÃÄÅÆÇÈÉÊËÌÍÎÏÐÑÒÓÔÕÖØÙÚÛÜÝÞŸŽŠŒ' }
   let(:lowercase) { 'abcdefghijklmnopqrstuvwxyzàáâãäåæçèéêëìíîïðñòóôõöøùúûüýþÿžšœ' }
   let(:default_types) do
-    "translate(@type,'#{uppercase}','#{lowercase}')='button' or" \
-" translate(@type,'#{uppercase}','#{lowercase}')='reset' or"\
-" translate(@type,'#{uppercase}','#{lowercase}')='submit' or"\
-" translate(@type,'#{uppercase}','#{lowercase}')='image'"
+    "translate(@type,'#{uppercase}','#{lowercase}')=translate('button','#{uppercase}','#{lowercase}') or " \
+    "translate(@type,'#{uppercase}','#{lowercase}')=translate('reset','#{uppercase}','#{lowercase}') or "\
+    "translate(@type,'#{uppercase}','#{lowercase}')=translate('submit','#{uppercase}','#{lowercase}') or "\
+    "translate(@type,'#{uppercase}','#{lowercase}')=translate('image','#{uppercase}','#{lowercase}')"
   end
 
   describe '#build' do
@@ -36,9 +36,10 @@
 
       it 'locates input or button element with specified type' do
         selector = {type: 'reset'}
+        type = "translate('reset','#{uppercase}','#{lowercase}')"
         built = {xpath: ".//*[(local-name()='button' and " \
-"translate(@type,'#{uppercase}','#{lowercase}')='reset') or " \
-"(local-name()='input' and (translate(@type,'#{uppercase}','#{lowercase}')='reset'))]"}
+"translate(@type,'#{uppercase}','#{lowercase}')=#{type}) or " \
+"(local-name()='input' and (translate(@type,'#{uppercase}','#{lowercase}')=#{type}))]"}
         expect(selector_builder.build(selector)).to eq built
       end
 
diff --git a/spec/unit/selector_builder/element_spec.rb b/spec/unit/selector_builder/element_spec.rb
index acd9de8f9..3e60675dc 100644
--- a/spec/unit/selector_builder/element_spec.rb
+++ b/spec/unit/selector_builder/element_spec.rb
@@ -574,7 +574,10 @@
         selector = {action: /ME/i}
         built = {xpath: './/*[contains(translate(@action,' \
 "'ABCDEFGHIJKLMNOPQRSTUVWXYZÀÁÂÃÄÅÆÇÈÉÊËÌÍÎÏÐÑÒÓÔÕÖØÙÚÛÜÝÞŸŽŠŒ'," \
-"'abcdefghijklmnopqrstuvwxyzàáâãäåæçèéêëìíîïðñòóôõöøùúûüýþÿžšœ'), 'me')]"}
+"'abcdefghijklmnopqrstuvwxyzàáâãäåæçèéêëìíîïðñòóôõöøùúûüýþÿžšœ'), " \
+"translate('me'," \
+"'ABCDEFGHIJKLMNOPQRSTUVWXYZÀÁÂÃÄÅÆÇÈÉÊËÌÍÎÏÐÑÒÓÔÕÖØÙÚÛÜÝÞŸŽŠŒ'," \
+"'abcdefghijklmnopqrstuvwxyzàáâãäåæçèéêëìíîïðñòóôõöøùúûüýþÿžšœ'))]"}
 
         expect(selector_builder.build(selector)).to eq built
       end
@@ -762,5 +765,51 @@
         expect(build_selector).to eq built
       end
     end
+
+    context 'with case-insensitive attributes' do
+      it 'respects case when locating uknown element with uknown attribute' do
+        expect(selector_builder.build(hreflang: 'en')).to eq(xpath: ".//*[@hreflang='en']")
+        expect(selector_builder.build(hreflang: /en/)).to eq(xpath: ".//*[contains(@hreflang, 'en')]")
+      end
+
+      it 'ignores case when locating uknown element with defined attribute' do
+        lhs = 'translate(@lang,' \
+  "'ABCDEFGHIJKLMNOPQRSTUVWXYZÀÁÂÃÄÅÆÇÈÉÊËÌÍÎÏÐÑÒÓÔÕÖØÙÚÛÜÝÞŸŽŠŒ'," \
+  "'abcdefghijklmnopqrstuvwxyzàáâãäåæçèéêëìíîïðñòóôõöøùúûüýþÿžšœ')"
+        rhs = "translate('en'," \
+  "'ABCDEFGHIJKLMNOPQRSTUVWXYZÀÁÂÃÄÅÆÇÈÉÊËÌÍÎÏÐÑÒÓÔÕÖØÙÚÛÜÝÞŸŽŠŒ'," \
+  "'abcdefghijklmnopqrstuvwxyzàáâãäåæçèéêëìíîïðñòóôõöøùúûüýþÿžšœ')"
+        expect(selector_builder.build(lang: 'en')).to eq(xpath: ".//*[#{lhs}=#{rhs}]")
+        expect(selector_builder.build(lang: /en/)).to eq(xpath: ".//*[contains(#{lhs}, #{rhs})]")
+        expect(selector_builder.build(tag_name: /a/, lang: 'en'))
+          .to eq(xpath: ".//*[contains(local-name(), 'a')][#{lhs}=#{rhs}]")
+        expect(selector_builder.build(tag_name: /a/, lang: /en/))
+          .to eq(xpath: ".//*[contains(local-name(), 'a')][contains(#{lhs}, #{rhs})]")
+      end
+
+      it 'ignores case when attribute is defined for element' do
+        lhs = 'translate(@hreflang,' \
+  "'ABCDEFGHIJKLMNOPQRSTUVWXYZÀÁÂÃÄÅÆÇÈÉÊËÌÍÎÏÐÑÒÓÔÕÖØÙÚÛÜÝÞŸŽŠŒ'," \
+  "'abcdefghijklmnopqrstuvwxyzàáâãäåæçèéêëìíîïðñòóôõöøùúûüýþÿžšœ')"
+        rhs = "translate('en'," \
+  "'ABCDEFGHIJKLMNOPQRSTUVWXYZÀÁÂÃÄÅÆÇÈÉÊËÌÍÎÏÐÑÒÓÔÕÖØÙÚÛÜÝÞŸŽŠŒ'," \
+  "'abcdefghijklmnopqrstuvwxyzàáâãäåæçèéêëìíîïðñòóôõöøùúûüýþÿžšœ')"
+        expect(selector_builder.build(tag_name: 'a', hreflang: 'en'))
+          .to eq(xpath: ".//*[local-name()='a'][#{lhs}=#{rhs}]")
+        expect(selector_builder.build(tag_name: 'a', hreflang: /en/))
+          .to eq(xpath: ".//*[local-name()='a'][contains(#{lhs}, #{rhs})]")
+      end
+
+      it 'respects case when attribute is not defined for element' do
+        expect(selector_builder.build(tag_name: 'table', hreflang: 'en'))
+          .to eq(xpath: ".//*[local-name()='table'][@hreflang='en']")
+        expect(selector_builder.build(tag_name: 'table', hreflang: /en/))
+          .to eq(xpath: ".//*[local-name()='table'][contains(@hreflang, 'en')]")
+        expect(selector_builder.build(tag_name: /a/, hreflang: 'en'))
+          .to eq(xpath: ".//*[contains(local-name(), 'a')][@hreflang='en']")
+        expect(selector_builder.build(tag_name: /a/, hreflang: /en/))
+          .to eq(xpath: ".//*[contains(local-name(), 'a')][contains(@hreflang, 'en')]")
+      end
+    end
   end
 end
diff --git a/spec/unit/selector_builder/text_field_spec.rb b/spec/unit/selector_builder/text_field_spec.rb
index b185d4112..6ae7a3b23 100644
--- a/spec/unit/selector_builder/text_field_spec.rb
+++ b/spec/unit/selector_builder/text_field_spec.rb
@@ -7,18 +7,18 @@
   let(:uppercase) { 'ABCDEFGHIJKLMNOPQRSTUVWXYZÀÁÂÃÄÅÆÇÈÉÊËÌÍÎÏÐÑÒÓÔÕÖØÙÚÛÜÝÞŸŽŠŒ' }
   let(:lowercase) { 'abcdefghijklmnopqrstuvwxyzàáâãäåæçèéêëìíîïðñòóôõöøùúûüýþÿžšœ' }
   let(:negative_types) do
-    "translate(@type,'#{uppercase}','#{lowercase}')!='file' and "\
-"translate(@type,'#{uppercase}','#{lowercase}')!='radio' and " \
-"translate(@type,'#{uppercase}','#{lowercase}')!='checkbox' and " \
-"translate(@type,'#{uppercase}','#{lowercase}')!='submit' and " \
-"translate(@type,'#{uppercase}','#{lowercase}')!='reset' and " \
-"translate(@type,'#{uppercase}','#{lowercase}')!='image' and " \
-"translate(@type,'#{uppercase}','#{lowercase}')!='button' and " \
-"translate(@type,'#{uppercase}','#{lowercase}')!='hidden' and " \
-"translate(@type,'#{uppercase}','#{lowercase}')!='range' and " \
-"translate(@type,'#{uppercase}','#{lowercase}')!='color' and " \
-"translate(@type,'#{uppercase}','#{lowercase}')!='date' and " \
-"translate(@type,'#{uppercase}','#{lowercase}')!='datetime-local'"
+    "translate(@type,'#{uppercase}','#{lowercase}')!=translate('file','#{uppercase}','#{lowercase}') and "\
+    "translate(@type,'#{uppercase}','#{lowercase}')!=translate('radio','#{uppercase}','#{lowercase}') and " \
+    "translate(@type,'#{uppercase}','#{lowercase}')!=translate('checkbox','#{uppercase}','#{lowercase}') and " \
+    "translate(@type,'#{uppercase}','#{lowercase}')!=translate('submit','#{uppercase}','#{lowercase}') and " \
+    "translate(@type,'#{uppercase}','#{lowercase}')!=translate('reset','#{uppercase}','#{lowercase}') and " \
+    "translate(@type,'#{uppercase}','#{lowercase}')!=translate('image','#{uppercase}','#{lowercase}') and " \
+    "translate(@type,'#{uppercase}','#{lowercase}')!=translate('button','#{uppercase}','#{lowercase}') and " \
+    "translate(@type,'#{uppercase}','#{lowercase}')!=translate('hidden','#{uppercase}','#{lowercase}') and " \
+    "translate(@type,'#{uppercase}','#{lowercase}')!=translate('range','#{uppercase}','#{lowercase}') and " \
+    "translate(@type,'#{uppercase}','#{lowercase}')!=translate('color','#{uppercase}','#{lowercase}') and " \
+    "translate(@type,'#{uppercase}','#{lowercase}')!=translate('date','#{uppercase}','#{lowercase}') and " \
+    "translate(@type,'#{uppercase}','#{lowercase}')!=translate('datetime-local','#{uppercase}','#{lowercase}')"
   end
 
   describe '#build' do
@@ -33,7 +33,7 @@
       it 'specified text field type that is text' do
         selector = {type: 'text'}
         built = {xpath: ".//*[local-name()='input']" \
-"[translate(@type,'#{uppercase}','#{lowercase}')='text']"}
+"[translate(@type,'#{uppercase}','#{lowercase}')=translate('text','#{uppercase}','#{lowercase}')]"}
 
         expect(selector_builder.build(selector)).to eq built
       end
@@ -41,7 +41,7 @@
       it 'specified text field type that is not text' do
         selector = {type: 'number'}
         built = {xpath: ".//*[local-name()='input']" \
-"[translate(@type,'#{uppercase}','#{lowercase}')='number']"}
+"[translate(@type,'#{uppercase}','#{lowercase}')=translate('number','#{uppercase}','#{lowercase}')]"}
 
         expect(selector_builder.build(selector)).to eq built
       end