diff --git a/components/script/dom/bindings/str.rs b/components/script/dom/bindings/str.rs
index 6601d8e6856c..596b2db14b2e 100644
--- a/components/script/dom/bindings/str.rs
+++ b/components/script/dom/bindings/str.rs
@@ -279,6 +279,20 @@ impl DOMString {
             _ => false
         }
     }
+
+    /// A valid date string should be "YYYY-MM-DD"
+    /// YYYY must be four or more digits, MM and DD both must be two digits
+    /// https://html.spec.whatwg.org/multipage/#valid-date-string
+    pub fn is_valid_date_string(&self) -> bool {
+        parse_date_string(&*self.0).is_ok()
+    }
+
+    /// A valid month string should be "YYYY-MM"
+    /// YYYY must be four or more digits, MM both must be two digits
+    /// https://html.spec.whatwg.org/multipage/#valid-month-string
+    pub fn is_valid_month_string(&self) -> bool {
+        parse_month_string(&*self.0).is_ok()
+    }
 }
 
 impl Borrow<str> for DOMString {
@@ -403,3 +417,90 @@ impl Extend<char> for DOMString {
         self.0.extend(iterable)
     }
 }
+
+/// https://html.spec.whatwg.org/multipage/#parse-a-month-string
+fn parse_month_string(value: &str) -> Result<(u32, u32), ()> {
+    // Step 1, 2, 3
+    let (year_int, month_int) = parse_month_component(value)?;
+
+    // Step 4
+    if value.split("-").nth(2).is_some() {
+        return Err(());
+    }
+    // Step 5
+    Ok((year_int, month_int))
+}
+
+/// https://html.spec.whatwg.org/multipage/#parse-a-date-string
+fn parse_date_string(value: &str) -> Result<(u32, u32, u32), ()> {
+    // Step 1, 2, 3
+    let (year_int, month_int, day_int) = parse_date_component(value)?;
+
+    // Step 4
+    if value.split('-').nth(3).is_some() {
+        return Err(());
+    }
+
+    // Step 5, 6
+    Ok((year_int, month_int, day_int))
+}
+
+/// https://html.spec.whatwg.org/multipage/#parse-a-month-component
+fn parse_month_component(value: &str) -> Result<(u32, u32), ()> {
+    // Step 3
+    let mut iterator = value.split('-');
+    let year = iterator.next().ok_or(())?;
+    let month = iterator.next().ok_or(())?;
+
+    // Step 1, 2
+    let year_int = year.parse::<u32>().map_err(|_| ())?;
+    if year.len() < 4 || year_int == 0 {
+        return Err(());
+    }
+
+    // Step 4, 5
+    let month_int = month.parse::<u32>().map_err(|_| ())?;
+    if month.len() != 2 ||  month_int > 12 || month_int < 1 {
+        return Err(());
+    }
+
+    // Step 6
+    Ok((year_int, month_int))
+}
+
+/// https://html.spec.whatwg.org/multipage/#parse-a-date-component
+fn parse_date_component(value: &str) -> Result<(u32, u32, u32), ()> {
+    // Step 1
+    let (year_int, month_int) = parse_month_component(value)?;
+
+    // Step 3, 4
+    let day = value.split('-').nth(2).ok_or(())?;
+    let day_int = day.parse::<u32>().map_err(|_| ())?;
+    if day.len() != 2 {
+        return Err(());
+    }
+
+    // Step 2, 5
+    let max_day = max_day_in_month(year_int, month_int)?;
+    if day_int == 0 || day_int > max_day {
+        return Err(());
+    }
+
+    // Step 6
+    Ok((year_int, month_int, day_int))
+}
+
+fn max_day_in_month(year_num: u32, month_num: u32) -> Result<u32, ()> {
+    match month_num {
+        1|3|5|7|8|10|12 => Ok(31),
+        4|6|9|11 => Ok(30),
+        2 => {
+            if year_num % 400 == 0 || (year_num % 4 == 0 && year_num % 100 != 0) {
+                Ok(29)
+            } else {
+                Ok(28)
+            }
+        },
+        _ => Err(())
+    }
+}
diff --git a/components/script/dom/htmlinputelement.rs b/components/script/dom/htmlinputelement.rs
index 0725fafcaaca..cbf4f483e0c8 100755
--- a/components/script/dom/htmlinputelement.rs
+++ b/components/script/dom/htmlinputelement.rs
@@ -875,6 +875,18 @@ impl HTMLInputElement {
                 content.strip_newlines();
                 content.strip_leading_and_trailing_ascii_whitespace();
             }
+            atom!("date") => {
+                let mut textinput = self.textinput.borrow_mut();
+                if !textinput.single_line_content().is_valid_date_string() {
+                    *textinput.single_line_content_mut() = "".into();
+                }
+            }
+            atom!("month") => {
+                let mut textinput = self.textinput.borrow_mut();
+                if !textinput.single_line_content().is_valid_month_string() {
+                    *textinput.single_line_content_mut() = "".into();
+                }
+            }
             atom!("color") => {
                 let mut textinput = self.textinput.borrow_mut();
 
@@ -1042,6 +1054,7 @@ impl VirtualMethods for HTMLInputElement {
                 let value = mutation.new_value(attr).map(|value| (**value).to_owned());
                 self.textinput.borrow_mut().set_content(
                     value.map_or(DOMString::new(), DOMString::from));
+                self.sanitize_value();
                 self.update_placeholder_shown_state();
             },
             &local_name!("name") if self.input_type.get() == InputType::InputRadio => {
@@ -1117,7 +1130,6 @@ impl VirtualMethods for HTMLInputElement {
         if let Some(ref s) = self.super_type() {
             s.bind_to_tree(tree_in_doc);
         }
-
         self.upcast::<Element>().check_ancestors_disabled_state_for_form_control();
     }
 
diff --git a/tests/wpt/metadata/MANIFEST.json b/tests/wpt/metadata/MANIFEST.json
index 18d4d794c2f7..68306f7ae97e 100644
--- a/tests/wpt/metadata/MANIFEST.json
+++ b/tests/wpt/metadata/MANIFEST.json
@@ -542997,7 +542997,7 @@
    "testharness"
   ],
   "html/semantics/forms/the-input-element/month.html": [
-   "1d833657f1db1e58fcc12a01af2ba06a665344aa",
+   "d0833c2b8ddd97c35200eb95ba0473795abf1f3b",
    "testharness"
   ],
   "html/semantics/forms/the-input-element/number.html": [
diff --git a/tests/wpt/metadata/html/semantics/forms/the-input-element/date.html.ini b/tests/wpt/metadata/html/semantics/forms/the-input-element/date.html.ini
index 241ad23a5e22..99eb0c7bba3b 100644
--- a/tests/wpt/metadata/html/semantics/forms/the-input-element/date.html.ini
+++ b/tests/wpt/metadata/html/semantics/forms/the-input-element/date.html.ini
@@ -5,10 +5,3 @@
 
   [The max attribute, if specified, must have a value that is a valid date string.]
     expected: FAIL
-
-  [User agents must not allow the user to set the value to a non-empty string that is not a valid date string.]
-    expected: FAIL
-
-  [Number of days]
-    expected: FAIL
-
diff --git a/tests/wpt/metadata/html/semantics/forms/the-input-element/month.html.ini b/tests/wpt/metadata/html/semantics/forms/the-input-element/month.html.ini
index 5bf6d6773888..dd41c559298c 100644
--- a/tests/wpt/metadata/html/semantics/forms/the-input-element/month.html.ini
+++ b/tests/wpt/metadata/html/semantics/forms/the-input-element/month.html.ini
@@ -1,32 +1,4 @@
 [month.html]
   type: testharness
-  [The value attribute, if specified and not empty, must have a value that is a valid month string]
-    expected: FAIL
-
-  [The min attribute, if specified, must have a value that is a valid month string.]
-    expected: FAIL
-
-  [The max attribute, if specified, must have a value that is a valid month string]
-    expected: FAIL
-
-  [User agents must not allow the user to set the value to a non-empty string that is not a valid month string.]
-    expected: FAIL
-
-  [When value attribute has two digits year value, the value,which is invalid, must return empty string.]
-    expected: FAIL
-
-  [When value is set with invalid value, the value must return empty string.]
-    expected: FAIL
-
-  [When value is given invalid value to non-empty valid string, the value must be same as before.]
-    expected: FAIL
-
   [When step attribute is given invalid value, it must ignore the invalid value and use defaul value instead.]
     expected: FAIL
-
-  [Month should be <= 13: If the value of the element is not a valid month string, then set it to the empty string instead.]
-    expected: FAIL
-
-  [Month should be > 0: If the value of the element is not a valid month string, then set it to the empty string instead.>]
-    expected: FAIL
-
diff --git a/tests/wpt/metadata/html/semantics/forms/the-input-element/telephone.html.ini b/tests/wpt/metadata/html/semantics/forms/the-input-element/telephone.html.ini
deleted file mode 100644
index c76c90b49c41..000000000000
--- a/tests/wpt/metadata/html/semantics/forms/the-input-element/telephone.html.ini
+++ /dev/null
@@ -1,11 +0,0 @@
-[telephone.html]
-  type: testharness
-  [The value attribute, if specified, must have a value that contains no "LF" (U+000A)]
-    expected: FAIL
-
-  [The value attribute, if specified, must have a value that contains no "CR" (U+000D)]
-    expected: FAIL
-
-  [The value sanitization algorithm is as follows: Strip line breaks from the value]
-    expected: FAIL
-
diff --git a/tests/wpt/metadata/html/semantics/forms/the-input-element/type-change-state.html.ini b/tests/wpt/metadata/html/semantics/forms/the-input-element/type-change-state.html.ini
index cc3c76ce1ab4..185dd9211147 100644
--- a/tests/wpt/metadata/html/semantics/forms/the-input-element/type-change-state.html.ini
+++ b/tests/wpt/metadata/html/semantics/forms/the-input-element/type-change-state.html.ini
@@ -6,12 +6,6 @@
   [change state from hidden to datetime]
     expected: FAIL
 
-  [change state from hidden to date]
-    expected: FAIL
-
-  [change state from hidden to month]
-    expected: FAIL
-
   [change state from hidden to week]
     expected: FAIL
 
@@ -27,12 +21,6 @@
   [change state from text to datetime]
     expected: FAIL
 
-  [change state from text to date]
-    expected: FAIL
-
-  [change state from text to month]
-    expected: FAIL
-
   [change state from text to week]
     expected: FAIL
 
@@ -48,12 +36,6 @@
   [change state from search to datetime]
     expected: FAIL
 
-  [change state from search to date]
-    expected: FAIL
-
-  [change state from search to month]
-    expected: FAIL
-
   [change state from search to week]
     expected: FAIL
 
@@ -69,12 +51,6 @@
   [change state from tel to datetime]
     expected: FAIL
 
-  [change state from tel to date]
-    expected: FAIL
-
-  [change state from tel to month]
-    expected: FAIL
-
   [change state from tel to week]
     expected: FAIL
 
@@ -99,12 +75,6 @@
   [change state from url to datetime]
     expected: FAIL
 
-  [change state from url to date]
-    expected: FAIL
-
-  [change state from url to month]
-    expected: FAIL
-
   [change state from url to week]
     expected: FAIL
 
@@ -138,12 +108,6 @@
   [change state from email to datetime]
     expected: FAIL
 
-  [change state from email to date]
-    expected: FAIL
-
-  [change state from email to month]
-    expected: FAIL
-
   [change state from email to week]
     expected: FAIL
 
@@ -159,12 +123,6 @@
   [change state from password to datetime]
     expected: FAIL
 
-  [change state from password to date]
-    expected: FAIL
-
-  [change state from password to month]
-    expected: FAIL
-
   [change state from password to week]
     expected: FAIL
 
@@ -192,12 +150,6 @@
   [change state from datetime to password]
     expected: FAIL
 
-  [change state from datetime to date]
-    expected: FAIL
-
-  [change state from datetime to month]
-    expected: FAIL
-
   [change state from datetime to week]
     expected: FAIL
 
@@ -207,99 +159,18 @@
   [change state from datetime to range]
     expected: FAIL
 
-  [change state from date to hidden]
-    expected: FAIL
-
-  [change state from date to checkbox]
-    expected: FAIL
-
-  [change state from date to radio]
-    expected: FAIL
-
-  [change state from date to submit]
-    expected: FAIL
-
-  [change state from date to image]
-    expected: FAIL
-
-  [change state from date to reset]
-    expected: FAIL
-
-  [change state from date to button]
-    expected: FAIL
-
-  [change state from date to email]
-    expected: FAIL
-
   [change state from date to datetime]
     expected: FAIL
 
-  [change state from date to month]
-    expected: FAIL
-
-  [change state from date to week]
-    expected: FAIL
-
-  [change state from date to number]
-    expected: FAIL
-
   [change state from date to range]
     expected: FAIL
 
-  [change state from month to hidden]
-    expected: FAIL
-
-  [change state from month to checkbox]
-    expected: FAIL
-
-  [change state from month to radio]
-    expected: FAIL
-
-  [change state from month to submit]
-    expected: FAIL
-
-  [change state from month to image]
-    expected: FAIL
-
-  [change state from month to reset]
-    expected: FAIL
-
-  [change state from month to button]
-    expected: FAIL
-
-  [change state from month to email]
-    expected: FAIL
-
-  [change state from month to datetime]
-    expected: FAIL
-
-  [change state from month to date]
-    expected: FAIL
-
-  [change state from month to week]
-    expected: FAIL
-
-  [change state from month to number]
+  [change state from date to range]
     expected: FAIL
 
   [change state from month to range]
     expected: FAIL
 
-  [change state from week to hidden]
-    expected: FAIL
-
-  [change state from week to checkbox]
-    expected: FAIL
-
-  [change state from week to radio]
-    expected: FAIL
-
-  [change state from week to submit]
-    expected: FAIL
-
-  [change state from week to image]
-    expected: FAIL
-
   [change state from week to reset]
     expected: FAIL
 
@@ -312,10 +183,10 @@
   [change state from week to datetime]
     expected: FAIL
 
-  [change state from week to date]
+  [change state from week to number]
     expected: FAIL
 
-  [change state from week to month]
+  [change state from week to hidden]
     expected: FAIL
 
   [change state from week to number]
@@ -324,6 +195,12 @@
   [change state from week to range]
     expected: FAIL
 
+  [change state from time to datetime]
+    expected: FAIL
+
+  [change state from time to range]
+    expected: FAIL
+
   [change state from number to hidden]
     expected: FAIL
 
@@ -351,12 +228,6 @@
   [change state from number to datetime]
     expected: FAIL
 
-  [change state from number to date]
-    expected: FAIL
-
-  [change state from number to month]
-    expected: FAIL
-
   [change state from number to week]
     expected: FAIL
 
@@ -390,12 +261,6 @@
   [change state from range to datetime]
     expected: FAIL
 
-  [change state from range to date]
-    expected: FAIL
-
-  [change state from range to month]
-    expected: FAIL
-
   [change state from range to week]
     expected: FAIL
 
@@ -408,12 +273,6 @@
   [change state from checkbox to datetime]
     expected: FAIL
 
-  [change state from checkbox to date]
-    expected: FAIL
-
-  [change state from checkbox to month]
-    expected: FAIL
-
   [change state from checkbox to week]
     expected: FAIL
 
@@ -429,12 +288,6 @@
   [change state from radio to datetime]
     expected: FAIL
 
-  [change state from radio to date]
-    expected: FAIL
-
-  [change state from radio to month]
-    expected: FAIL
-
   [change state from radio to week]
     expected: FAIL
 
@@ -450,12 +303,6 @@
   [change state from submit to datetime]
     expected: FAIL
 
-  [change state from submit to date]
-    expected: FAIL
-
-  [change state from submit to month]
-    expected: FAIL
-
   [change state from submit to week]
     expected: FAIL
 
@@ -471,12 +318,6 @@
   [change state from image to datetime]
     expected: FAIL
 
-  [change state from image to date]
-    expected: FAIL
-
-  [change state from image to month]
-    expected: FAIL
-
   [change state from image to week]
     expected: FAIL
 
@@ -492,12 +333,6 @@
   [change state from reset to datetime]
     expected: FAIL
 
-  [change state from reset to date]
-    expected: FAIL
-
-  [change state from reset to month]
-    expected: FAIL
-
   [change state from reset to week]
     expected: FAIL
 
@@ -513,12 +348,6 @@
   [change state from button to datetime]
     expected: FAIL
 
-  [change state from button to date]
-    expected: FAIL
-
-  [change state from button to month]
-    expected: FAIL
-
   [change state from button to week]
     expected: FAIL
 
@@ -573,12 +402,6 @@
   [change state from datetime-local to email]
     expected: FAIL
 
-  [change state from datetime-local to date]
-    expected: FAIL
-
-  [change state from datetime-local to month]
-    expected: FAIL
-
   [change state from datetime-local to week]
     expected: FAIL
 
@@ -588,12 +411,6 @@
   [change state from datetime-local to range]
     expected: FAIL
 
-  [change state from date to datetime-local]
-    expected: FAIL
-
-  [change state from month to datetime-local]
-    expected: FAIL
-
   [change state from week to datetime-local]
     expected: FAIL
 
@@ -621,7 +438,6 @@
   [change state from button to datetime-local]
     expected: FAIL
 
-
   [change state from datetime-local to text]
     expected: FAIL
 
@@ -637,55 +453,33 @@
   [change state from datetime-local to password]
     expected: FAIL
 
-
-  [change state from date to text]
-    expected: FAIL
-
-  [change state from date to search]
-    expected: FAIL
-
-  [change state from date to tel]
-    expected: FAIL
-
-  [change state from date to url]
-    expected: FAIL
-
-  [change state from date to password]
-    expected: FAIL
-
-
-  [change state from month to text]
-    expected: FAIL
-
-  [change state from month to search]
+  [change state from week to text]
     expected: FAIL
 
-  [change state from month to tel]
+  [change state from week to search]
     expected: FAIL
 
-  [change state from month to url]
+  [change state from week to tel]
     expected: FAIL
 
-  [change state from month to password]
+  [change state from week to url]
     expected: FAIL
 
-
-  [change state from week to text]
+  [change state from week to password]
     expected: FAIL
 
-  [change state from week to search]
+  [change state from week to checkbox]
     expected: FAIL
 
-  [change state from week to tel]
+  [change state from week to radio]
     expected: FAIL
 
-  [change state from week to url]
+  [change state from week to submit]
     expected: FAIL
 
-  [change state from week to password]
+  [change state from week to image]
     expected: FAIL
 
-
   [change state from number to text]
     expected: FAIL
 
@@ -701,40 +495,29 @@
   [change state from number to password]
     expected: FAIL
 
-
-  [change state from color to datetime-local]
-    expected: FAIL
-
-  [change state from color to date]
-    expected: FAIL
-
-  [change state from color to month]
-    expected: FAIL
-
-  [change state from color to week]
+  [change state from range to text]
     expected: FAIL
 
-  [change state from color to number]
+  [change state from range to search]
     expected: FAIL
 
-  [change state from color to range]
+  [change state from range to tel]
     expected: FAIL
 
-
-  [change state from time to range]
+  [change state from range to url]
     expected: FAIL
 
-  [change state from range to text]
+  [change state from range to password]
     expected: FAIL
 
-  [change state from range to search]
+  [change state from color to datetime-local]
     expected: FAIL
 
-  [change state from range to tel]
+  [change state from color to week]
     expected: FAIL
 
-  [change state from range to url]
+  [change state from color to number]
     expected: FAIL
 
-  [change state from range to password]
+  [change state from color to range]
     expected: FAIL
diff --git a/tests/wpt/metadata/html/semantics/forms/the-input-element/url.html.ini b/tests/wpt/metadata/html/semantics/forms/the-input-element/url.html.ini
deleted file mode 100644
index 2adffb5fdd83..000000000000
--- a/tests/wpt/metadata/html/semantics/forms/the-input-element/url.html.ini
+++ /dev/null
@@ -1,8 +0,0 @@
-[url.html]
-  type: testharness
-  [The value sanitization algorithm is as follows: Strip line breaks from the value]
-    expected: FAIL
-
-  [The value sanitization algorithm is as follows: Strip leading and trailing whitespace from the value.]
-    expected: FAIL
-
diff --git a/tests/wpt/metadata/html/semantics/forms/the-input-element/valueMode.html.ini b/tests/wpt/metadata/html/semantics/forms/the-input-element/valueMode.html.ini
index 8c54f4d21d99..4dd99f109cdc 100644
--- a/tests/wpt/metadata/html/semantics/forms/the-input-element/valueMode.html.ini
+++ b/tests/wpt/metadata/html/semantics/forms/the-input-element/valueMode.html.ini
@@ -6,18 +6,6 @@
   [value IDL attribute of input type datetime with value attribute]
     expected: FAIL
 
-  [value IDL attribute of input type date without value attribute]
-    expected: FAIL
-
-  [value IDL attribute of input type date with value attribute]
-    expected: FAIL
-
-  [value IDL attribute of input type month without value attribute]
-    expected: FAIL
-
-  [value IDL attribute of input type month with value attribute]
-    expected: FAIL
-
   [value IDL attribute of input type week without value attribute]
     expected: FAIL
 
diff --git a/tests/wpt/web-platform-tests/html/semantics/forms/the-input-element/month.html b/tests/wpt/web-platform-tests/html/semantics/forms/the-input-element/month.html
index 15fa76dd4dd0..99be9bca673d 100644
--- a/tests/wpt/web-platform-tests/html/semantics/forms/the-input-element/month.html
+++ b/tests/wpt/web-platform-tests/html/semantics/forms/the-input-element/month.html
@@ -13,6 +13,9 @@
   <body>
     <h1>Inputs Month</h1>
     <div style="display: none">
+      <input id="valid_value_1" type="month" value="20133-12" />
+      <input id="valid_value_2" type="month" value="2013-12" />
+      <input id="valid_value_3" type="month" value="0003-01" />
       <input id="valid" type="month" value="2011-11" min="2011-01" max="2011-12" />
       <input id="invalid_value" type="month" value="invalid-month" min="2011-01" max="2011-12"/>
       <input id="value_can_be_empty_string" type="month" value="2013-06" />
@@ -21,11 +24,27 @@ <h1>Inputs Month</h1>
       <input id="step_attribute_is_invalid_value" type="month" value="2013-06" step="invalid_step_value" />
       <input id="invalid_month_too_high" type="month" value="2013-13" />
       <input id="invalid_month_too_low" type="month" value="2013-00" />
+      <input id="invalid_year_all_zero" type="month" value="0000-10" />
+      <input id="invalid_month_with_one_number" type="month" value="2013-1" />
+      <input id="invalid_month_non_numerical" type="month" value="2013-abc" />
+      <input id="invalid_date_additional_tuples" type="month" value="2013-11-1-1" />
     </div>
 
     <div id="log"></div>
 
     <script>
+      test(function() {
+        assert_equals(document.getElementById("valid_value_1").value, "20133-12")
+      }, "year can be more than four digits");
+
+      test(function() {
+        assert_equals(document.getElementById("valid_value_2").value, "2013-12")
+      }, "valid value test");
+
+      test(function() {
+        assert_equals(document.getElementById("valid_value_3").value, "0003-01")
+      }, "year can contain prefixes of zero, as long as there are at least four digits");
+
       test(function() {
         assert_equals(document.getElementById("valid").type, "month")
       }, "month type support on input element");
@@ -60,6 +79,22 @@ <h1>Inputs Month</h1>
       test(function() {
         assert_equals(document.getElementById("invalid_month_too_low").value, "");
       }, "Month should be > 0: If the value of the element is not a valid month string, then set it to the empty string instead.>");
+
+      test(function() {
+        assert_equals(document.getElementById("invalid_year_all_zero").value, "");
+      }, "Year should be > 0: If the value of the element is not a valid year string, then set it to the empty string instead.>");
+
+      test(function() {
+        assert_equals(document.getElementById("invalid_month_with_one_number").value, "");
+      }, "Month should be two digits: If the value of the element is not a valid month string, then set it to the empty string instead.>");
+
+      test(function() {
+        assert_equals(document.getElementById("invalid_month_non_numerical").value, "");
+      }, "Month should be two digits not characters: If the value of the element is not a valid month string, then set it to the empty string instead.>");
+
+      test(function() {
+        assert_equals(document.getElementById("invalid_date_additional_tuples").value, "");
+      }, "Value should be two parts: If the value of the element is not a valid month string, then set it to the empty string instead.>");
     </script>
   </body>
 </html>