diff --git a/Libraries/LibWeb/HTML/HTMLInputElement.cpp b/Libraries/LibWeb/HTML/HTMLInputElement.cpp
index 8818ec4f76a..199a0ea76db 100644
--- a/Libraries/LibWeb/HTML/HTMLInputElement.cpp
+++ b/Libraries/LibWeb/HTML/HTMLInputElement.cpp
@@ -2475,8 +2475,23 @@ double HTMLInputElement::default_step() const
     if (type_state() == TypeAttributeState::Time)
         return 60;
 
-    dbgln("HTMLInputElement::default_step() not implemented for input type {}", type());
-    return 0;
+    // https://html.spec.whatwg.org/multipage/input.html#date-state-(type=date):concept-input-step-default
+    if (type_state() == TypeAttributeState::Date)
+        return 1;
+
+    // https://html.spec.whatwg.org/multipage/input.html#month-state-(type=month):concept-input-step-default
+    if (type_state() == TypeAttributeState::Month)
+        return 1;
+
+    // https://html.spec.whatwg.org/multipage/input.html#week-state-(type=week):concept-input-step-default
+    if (type_state() == TypeAttributeState::Week)
+        return 1;
+
+    // https://html.spec.whatwg.org/multipage/input.html#local-date-and-time-state-(type=datetime-local):concept-input-step-default
+    if (type_state() == TypeAttributeState::LocalDateAndTime)
+        return 60;
+
+    VERIFY_NOT_REACHED();
 }
 
 // https://html.spec.whatwg.org/multipage/input.html#concept-input-step-scale
@@ -2494,8 +2509,23 @@ double HTMLInputElement::step_scale_factor() const
     if (type_state() == TypeAttributeState::Time)
         return 1000;
 
-    dbgln("HTMLInputElement::step_scale_factor() not implemented for input type {}", type());
-    return 0;
+    // https://html.spec.whatwg.org/multipage/input.html#date-state-(type=date):concept-input-step-scale
+    if (type_state() == TypeAttributeState::Date)
+        return 86400000;
+
+    // https://html.spec.whatwg.org/multipage/input.html#month-state-(type=month):concept-input-step-scale
+    if (type_state() == TypeAttributeState::Month)
+        return 1;
+
+    // https://html.spec.whatwg.org/multipage/input.html#week-state-(type=week):concept-input-step-scale
+    if (type_state() == TypeAttributeState::Week)
+        return 604800000;
+
+    // https://html.spec.whatwg.org/multipage/input.html#local-date-and-time-state-(type=datetime-local):concept-input-step-scale
+    if (type_state() == TypeAttributeState::LocalDateAndTime)
+        return 1000;
+
+    VERIFY_NOT_REACHED();
 }
 
 // https://html.spec.whatwg.org/multipage/input.html#concept-input-step
diff --git a/Tests/LibWeb/Text/expected/wpt-import/html/semantics/forms/constraints/form-validation-validity-stepMismatch.txt b/Tests/LibWeb/Text/expected/wpt-import/html/semantics/forms/constraints/form-validation-validity-stepMismatch.txt
new file mode 100644
index 00000000000..b26670b0922
--- /dev/null
+++ b/Tests/LibWeb/Text/expected/wpt-import/html/semantics/forms/constraints/form-validation-validity-stepMismatch.txt
@@ -0,0 +1,34 @@
+Harness status: OK
+
+Found 28 tests
+
+24 Pass
+4 Fail
+Pass	[INPUT in DATE status] The step attribute is not set
+Pass	[INPUT in DATE status] The value attibute is empty string
+Pass	[INPUT in DATE status] The value must match the step
+Pass	[INPUT in DATE status] The value must mismatch the step
+Pass	[INPUT in MONTH status] The step attribute is not set
+Pass	[INPUT in MONTH status] The value attibute is empty string
+Pass	[INPUT in MONTH status] The value must match the step
+Pass	[INPUT in MONTH status] The value must mismatch the step
+Pass	[INPUT in WEEK status] The step attribute is not set
+Pass	[INPUT in WEEK status] The value attibute is empty string
+Fail	[INPUT in WEEK status] The value must match the step
+Fail	[INPUT in WEEK status] The value must mismatch the step
+Pass	[INPUT in TIME status] The step attribute is not set
+Pass	[INPUT in TIME status] The value attibute is empty string
+Pass	[INPUT in TIME status] The value must match the step
+Pass	[INPUT in TIME status] The value must mismatch the step
+Pass	[INPUT in DATETIME-LOCAL status] The step attribute is not set
+Pass	[INPUT in DATETIME-LOCAL status] The value attibute is empty string
+Pass	[INPUT in DATETIME-LOCAL status] The value must match the step
+Pass	[INPUT in DATETIME-LOCAL status] The value must mismatch the step
+Pass	[INPUT in NUMBER status] The step attribute is not set
+Pass	[INPUT in NUMBER status] The step attribute is not set and the value attribute is a floating number
+Pass	[INPUT in NUMBER status] The value attribute is empty string
+Pass	[INPUT in NUMBER status] The value must match the step
+Pass	[INPUT in NUMBER status] The value must mismatch the step
+Fail	[INPUT in NUMBER status] No step mismatch when step is a floating number and value is its integral multiple
+Fail	[INPUT in NUMBER status] No step mismatch when step is a floating number in exponent format and value is its integral multiple
+Pass	[INPUT in NUMBER status] Step mismatch when step is a very small floating number and value is not its integral multiple
\ No newline at end of file
diff --git a/Tests/LibWeb/Text/expected/wpt-import/html/semantics/forms/the-input-element/input-stepdown-weekmonth.txt b/Tests/LibWeb/Text/expected/wpt-import/html/semantics/forms/the-input-element/input-stepdown-weekmonth.txt
new file mode 100644
index 00000000000..f693e278ecf
--- /dev/null
+++ b/Tests/LibWeb/Text/expected/wpt-import/html/semantics/forms/the-input-element/input-stepdown-weekmonth.txt
@@ -0,0 +1,7 @@
+Harness status: OK
+
+Found 2 tests
+
+2 Pass
+Pass	Calling stepDown() on input - month - where value < min should not modify value.
+Pass	Calling stepDown() on input - week - where value < min should not modify value.
\ No newline at end of file
diff --git a/Tests/LibWeb/Text/expected/wpt-import/html/semantics/forms/the-input-element/input-stepdown.txt b/Tests/LibWeb/Text/expected/wpt-import/html/semantics/forms/the-input-element/input-stepdown.txt
new file mode 100644
index 00000000000..79aea5478fe
--- /dev/null
+++ b/Tests/LibWeb/Text/expected/wpt-import/html/semantics/forms/the-input-element/input-stepdown.txt
@@ -0,0 +1,10 @@
+Harness status: OK
+
+Found 5 tests
+
+5 Pass
+Pass	Forms
+Pass	Calling stepDown() on input - number - where value < min should not modify value.
+Pass	Calling stepDown() on input - date - where value < min should not modify value.
+Pass	Calling stepDown() on input - datetime-local - where value < min should not modify value.
+Pass	Calling stepDown() on input - time - where value < min should not modify value.
\ No newline at end of file
diff --git a/Tests/LibWeb/Text/expected/wpt-import/html/semantics/forms/the-input-element/input-stepup-weekmonth.txt b/Tests/LibWeb/Text/expected/wpt-import/html/semantics/forms/the-input-element/input-stepup-weekmonth.txt
new file mode 100644
index 00000000000..7a128deef02
--- /dev/null
+++ b/Tests/LibWeb/Text/expected/wpt-import/html/semantics/forms/the-input-element/input-stepup-weekmonth.txt
@@ -0,0 +1,7 @@
+Harness status: OK
+
+Found 2 tests
+
+2 Pass
+Pass	Calling stepUp() on input -month- where value > max should not modify value.
+Pass	Calling stepUp() on input -week- where value > max should not modify value.
\ No newline at end of file
diff --git a/Tests/LibWeb/Text/expected/wpt-import/html/semantics/forms/the-input-element/input-stepup.txt b/Tests/LibWeb/Text/expected/wpt-import/html/semantics/forms/the-input-element/input-stepup.txt
new file mode 100644
index 00000000000..ea00ce5a56f
--- /dev/null
+++ b/Tests/LibWeb/Text/expected/wpt-import/html/semantics/forms/the-input-element/input-stepup.txt
@@ -0,0 +1,10 @@
+Harness status: OK
+
+Found 5 tests
+
+5 Pass
+Pass	Forms
+Pass	Calling stepUp() on input -number- where value > max should not modify value.
+Pass	Calling stepUp() on input -date- where value > max should not modify value.
+Pass	Calling stepUp() on input -datetime-local- where value > max should not modify value.
+Pass	Calling stepUp() on input -time- where value > max should not modify value.
\ No newline at end of file
diff --git a/Tests/LibWeb/Text/expected/wpt-import/html/semantics/forms/the-input-element/month.txt b/Tests/LibWeb/Text/expected/wpt-import/html/semantics/forms/the-input-element/month.txt
new file mode 100644
index 00000000000..9cab370c9b1
--- /dev/null
+++ b/Tests/LibWeb/Text/expected/wpt-import/html/semantics/forms/the-input-element/month.txt
@@ -0,0 +1,21 @@
+Harness status: OK
+
+Found 15 tests
+
+14 Pass
+1 Fail
+Pass	year can be more than four digits
+Pass	valid value test
+Pass	year can contain prefixes of zero, as long as there are at least four digits
+Pass	month type support on input element
+Pass	User agents must not allow the user to set the value to a non-empty string that is not a valid month string.
+Pass	Month value can be empty string.
+Pass	When value attribute has two digits year value, the value,which is invalid, must return empty string.
+Pass	When value is set with invalid value, the value must return empty string.
+Pass	When step attribute is given invalid value, it must ignore the invalid value and use defaul value instead.
+Pass	Month should be <= 13: If the value of the element is not a valid month string, then set it to the empty string instead.
+Pass	Month should be > 0: If the value of the element is not a valid month string, then set it to the empty string instead.>
+Fail	Year should be > 0: If the value of the element is not a valid year string, then set it to the empty string instead.>
+Pass	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.>
+Pass	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.>
+Pass	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.>
\ No newline at end of file
diff --git a/Tests/LibWeb/Text/input/wpt-import/html/semantics/forms/constraints/form-validation-validity-stepMismatch.html b/Tests/LibWeb/Text/input/wpt-import/html/semantics/forms/constraints/form-validation-validity-stepMismatch.html
new file mode 100644
index 00000000000..4eb19a9b54e
--- /dev/null
+++ b/Tests/LibWeb/Text/input/wpt-import/html/semantics/forms/constraints/form-validation-validity-stepMismatch.html
@@ -0,0 +1,81 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>The constraint validation API Test: element.validity.stepMismatch</title>
+<link rel="author" title="Intel" href="http://www.intel.com/">
+<link rel="help" href="https://html.spec.whatwg.org/multipage/#dom-validitystate-stepmismatch">
+<link rel="help" href="https://html.spec.whatwg.org/multipage/#the-constraint-validation-api">
+<script src="../../../../resources/testharness.js"></script>
+<script src="../../../../resources/testharnessreport.js"></script>
+<script src="support/validator.js"></script>
+<div id="log"></div>
+<script>
+  //set step = 2 * default step * factor
+  var testElements = [
+    {
+      tag: "input",
+      types: ["date"],
+      testData: [
+        {conditions: {step: "", value: "2000-01-01"}, expected: false, name: "[target] The step attribute is not set"},
+        {conditions: {step: 2, value: ""}, expected: false, name: "[target] The value attibute is empty string"},
+        {conditions: {step: 2, value: "1970-01-03"}, expected: false, name: "[target] The value must match the step"},
+        {conditions: {step: 2, value: "1970-01-02"}, expected: true, name: "[target] The value must mismatch the step"}
+      ]
+    },
+    {
+      tag: "input",
+      types: ["month"],
+      testData: [
+        {conditions: {step: "", value: "2000-01"}, expected: false, name: "[target] The step attribute is not set"},
+        {conditions: {step: 2, value: ""}, expected: false, name: "[target] The value attibute is empty string"},
+        {conditions: {step: 2, value: "1970-03"}, expected: false, name: "[target] The value must match the step"},
+        {conditions: {step: 2, value: "1970-04"}, expected: true, name: "[target] The value must mismatch the step"}
+      ]
+    },
+    {
+      tag: "input",
+      types: ["week"],
+      testData: [
+        {conditions: {step: "", value: "1970-W01"}, expected: false, name: "[target] The step attribute is not set"},
+        {conditions: {step: 2, value: ""}, expected: false, name: "[target] The value attibute is empty string"},
+        {conditions: {step: 2, value: "1970-W03"}, expected: false, name: "[target] The value must match the step"},
+        {conditions: {step: 2, value: "1970-W04"}, expected: true, name: "[target] The value must mismatch the step"}
+      ]
+    },
+    {
+      tag: "input",
+      types: ["time"],
+      testData: [
+        {conditions: {step: "", value: "12:00:00"}, expected: false, name: "[target] The step attribute is not set"},
+        {conditions: {step: 2 * 60, value: ""}, expected: false, name: "[target] The value attibute is empty string"},
+        {conditions: {step: 2 * 60, value: "12:02:00"}, expected: false, name: "[target] The value must match the step"},
+        {conditions: {step: 2 * 60, value: "12:03:00"}, expected: true, name: "[target] The value must mismatch the step"}
+      ]
+    },
+    {
+      tag: "input",
+      types: ["datetime-local"],
+      testData: [
+        {conditions: {step: "", value: "2000-01-01T12:00:00"}, expected: false, name: "[target] The step attribute is not set"},
+        {conditions: {step: 2 * 60, value: ""}, expected: false, name: "[target] The value attibute is empty string"},
+        {conditions: {step: 2 * 60, value: "1970-01-01T12:02:00"}, expected: false, name: "[target] The value must match the step"},
+        {conditions: {step: 2 * 60, value: "1970-01-01T12:03:00"}, expected: true, name: "[target] The value must mismatch the step"}
+      ]
+    },
+    {
+      tag: "input",
+      types: ["number"],
+      testData: [
+        {conditions: {step: "", value: "1"}, expected: false, name: "[target] The step attribute is not set"},
+        {conditions: {step: "", value: "-.8"}, expected: true, name: "[target] The step attribute is not set and the value attribute is a floating number"},
+        {conditions: {step: 2 * 1 * 1, value: ""}, expected: false, name: "[target] The value attribute is empty string"},
+        {conditions: {step: 2 * 1 * 1, value: "2"}, expected: false, name: "[target] The value must match the step"},
+        {conditions: {step: 2 * 1 * 1, value: "3"}, expected: true, name: "[target] The value must mismatch the step"},
+        {conditions: {step: 0.003, value: "3.6"}, expected: false, name: "[target] No step mismatch when step is a floating number and value is its integral multiple"},
+        {conditions: {step: 1e-12, value: "-12345678.9"}, expected: false, name: "[target] No step mismatch when step is a floating number in exponent format and value is its integral multiple"},
+        {conditions: {step: 3e-15, value: "17"}, expected: true, name: "[target] Step mismatch when step is a very small floating number and value is not its integral multiple"},
+      ]
+    }
+  ];
+
+  validator.run_test(testElements, "stepMismatch");
+</script>
diff --git a/Tests/LibWeb/Text/input/wpt-import/html/semantics/forms/the-input-element/input-stepdown-weekmonth.html b/Tests/LibWeb/Text/input/wpt-import/html/semantics/forms/the-input-element/input-stepdown-weekmonth.html
new file mode 100644
index 00000000000..2adf06f71ea
--- /dev/null
+++ b/Tests/LibWeb/Text/input/wpt-import/html/semantics/forms/the-input-element/input-stepdown-weekmonth.html
@@ -0,0 +1,22 @@
+<!DOCTYPE HTML>
+<html>
+<title>Forms</title>
+<script src="../../../../resources/testharness.js"></script>
+<script src="../../../../resources/testharnessreport.js"></script>
+<h3>input_stepDown</h3>
+<input type="month" id="month_input" min="2011-02" step="1" value="2010-02">
+<input type="week" id="week_input" min="2011-W02" step="1" value="2010-W02">
+
+<script>
+   function testStepDownOverflow(id, value, type) {
+      test(function() {
+        var input = document.getElementById(id);
+        input.stepDown();
+        assert_equals(input.value, value, "value shouldn't change.");
+      }, "Calling stepDown() on input - " + type + " - where value < min should not modify value.");
+    }
+
+    testStepDownOverflow("month_input", "2010-02", "month");
+    testStepDownOverflow("week_input", "2010-W02", "week");
+</script>
+</html>
diff --git a/Tests/LibWeb/Text/input/wpt-import/html/semantics/forms/the-input-element/input-stepdown.html b/Tests/LibWeb/Text/input/wpt-import/html/semantics/forms/the-input-element/input-stepdown.html
new file mode 100644
index 00000000000..cbebcd5b62a
--- /dev/null
+++ b/Tests/LibWeb/Text/input/wpt-import/html/semantics/forms/the-input-element/input-stepdown.html
@@ -0,0 +1,43 @@
+<!DOCTYPE HTML>
+<html>
+<title>Forms</title>
+<script src="../../../../resources/testharness.js"></script>
+<script src="../../../../resources/testharnessreport.js"></script>
+<h3>input_stepDown</h3>
+<input type='number' id='input_number'>
+<input type="number" id="number_input" min="300" step="1" value="200">
+<input type="date" id="date_input"  min="2011-02-10" step="1" value="2010-02-10">
+<input type="datetime-local" id="dtl_input" min="2011-02-10T20:13" step="1" value="2010-02-10T20:13">
+<input type="time" id="time_input" min="21:13" step="60" value="20:13">
+
+<script>
+    var input_number = document.getElementById("input_number");
+    input_number.max = "30";
+    input_number.step = "3";
+    input_number.value = "30";
+    input_number.stepDown(5);
+
+    if (typeof(input_number.stepDown) == "function") {
+      test(function() {
+        assert_equals(input_number.value, "15", "call of stepDown method is failed.");
+      });
+    } else {
+      test(function() {
+        assert_unreached("stepDown attribute is not exist.");
+      });
+    }
+
+   function testStepDownOverflow(id, value, type) {
+      test(function() {
+        var input = document.getElementById(id);
+        input.stepDown();
+        assert_equals(input.value, value, "value shouldn't change.");
+      }, "Calling stepDown() on input - " + type + " - where value < min should not modify value.");
+    }
+
+    testStepDownOverflow("number_input", "200", "number");
+    testStepDownOverflow("date_input", "2010-02-10", "date");
+    testStepDownOverflow("dtl_input", "2010-02-10T20:13", "datetime-local");
+    testStepDownOverflow("time_input", "20:13", "time");
+</script>
+</html>
diff --git a/Tests/LibWeb/Text/input/wpt-import/html/semantics/forms/the-input-element/input-stepup-weekmonth.html b/Tests/LibWeb/Text/input/wpt-import/html/semantics/forms/the-input-element/input-stepup-weekmonth.html
new file mode 100644
index 00000000000..c4d6d82f3dc
--- /dev/null
+++ b/Tests/LibWeb/Text/input/wpt-import/html/semantics/forms/the-input-element/input-stepup-weekmonth.html
@@ -0,0 +1,22 @@
+<!DOCTYPE HTML>
+<html>
+<title>Forms</title>
+<script src="../../../../resources/testharness.js"></script>
+<script src="../../../../resources/testharnessreport.js"></script>
+<h3>input_stepUp</h3>
+<input type="month" id="month_input" max="2009-02" step="1" value="2010-02">
+<input type="week" id="week_input" max="2009-W02" step="1" value="2010-W02">
+
+<script>
+    function testStepUpOverflow(id, value, type) {
+      test(function() {
+        var input = document.getElementById(id);
+        input.stepUp();
+        assert_equals(input.value, value, "value shouldn't change.");
+      }, "Calling stepUp() on input -" + type + "- where value > max should not modify value.");
+    }
+
+    testStepUpOverflow("month_input", "2010-02", "month");
+    testStepUpOverflow("week_input", "2010-W02", "week");
+</script>
+</html>
diff --git a/Tests/LibWeb/Text/input/wpt-import/html/semantics/forms/the-input-element/input-stepup.html b/Tests/LibWeb/Text/input/wpt-import/html/semantics/forms/the-input-element/input-stepup.html
new file mode 100644
index 00000000000..d8e0529200e
--- /dev/null
+++ b/Tests/LibWeb/Text/input/wpt-import/html/semantics/forms/the-input-element/input-stepup.html
@@ -0,0 +1,44 @@
+<!DOCTYPE HTML>
+<html>
+<title>Forms</title>
+<script src="../../../../resources/testharness.js"></script>
+<script src="../../../../resources/testharnessreport.js"></script>
+<h3>input_stepUp</h3>
+<input type='number' id='input_number'> <br/>
+<input type="number" id="number_input" max="100" step="1" value="200">
+<input type="date" id="date_input"  max="2009-02-10" step="1" value="2010-02-10">
+<input type="datetime-local" id="dtl_input" max="2009-02-10T20:13" step="1" value="2010-02-10T20:13">
+<input type="time" id="time_input" max="19:13" step="60" value="20:13">
+
+<script>
+
+    var input_number = document.getElementById("input_number");
+    input_number.max = "30";
+    input_number.step = "3";
+    input_number.value = "0";
+    input_number.stepUp(5);
+
+    if (typeof(input_number.stepUp) == "function") {
+      test(function() {
+        assert_equals(input_number.value, "15", "call of stepUp method is failed.");
+      });
+    } else {
+      test(function() {
+        assert_unreached("stepUp attribute is not exist.");
+      });
+    }
+
+    function testStepUpOverflow(id, value, type) {
+      test(function() {
+        var input = document.getElementById(id);
+        input.stepUp();
+        assert_equals(input.value, value, "value shouldn't change.");
+      }, "Calling stepUp() on input -" + type + "- where value > max should not modify value.");
+    }
+
+    testStepUpOverflow("number_input", "200", "number");
+    testStepUpOverflow("date_input", "2010-02-10", "date");
+    testStepUpOverflow("dtl_input", "2010-02-10T20:13", "datetime-local");
+    testStepUpOverflow("time_input", "20:13", "time");
+</script>
+</html>
diff --git a/Tests/LibWeb/Text/input/wpt-import/html/semantics/forms/the-input-element/month.html b/Tests/LibWeb/Text/input/wpt-import/html/semantics/forms/the-input-element/month.html
new file mode 100644
index 00000000000..43aea1df166
--- /dev/null
+++ b/Tests/LibWeb/Text/input/wpt-import/html/semantics/forms/the-input-element/month.html
@@ -0,0 +1,100 @@
+<!DOCTYPE html>
+<html>
+  <head>
+    <title>Inputs Month</title>
+    <link rel="author" title="Morishita Hiromitsu" href="mailto:hero@asterisk-works.jp">
+    <link rel="author" title="kaseijin" href="mailto:pcmkas@gmail.com">
+    <link rel="author" title="Denis Ah-Kang" href="mailto:denis@w3.org">
+    <link rel="help" href="https://html.spec.whatwg.org/multipage/#months">
+    <link rel="help" href="https://html.spec.whatwg.org/multipage/#month-state-(type=month)">
+    <script src="../../../../resources/testharness.js"></script>
+    <script src="../../../../resources/testharnessreport.js"></script>
+  </head>
+  <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" />
+      <input id="invalid_value_with_two_digits_year" type="month" value="13-06" />
+      <input id="invalid_value_is_set" type="month" />
+      <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");
+
+      test(function() {
+        assert_equals(document.getElementById("invalid_value").value, "")
+      }, "User agents must not allow the user to set the value to a non-empty string that is not a valid month string.");
+
+      test(function() {
+        document.getElementById("value_can_be_empty_string").value = "";
+        assert_equals(document.getElementById("value_can_be_empty_string").value, "")
+      }, "Month value can be empty string.");
+
+      test(function() {
+        assert_equals(document.getElementById("invalid_value_with_two_digits_year").value, "")
+      }, "When value attribute has two digits year value, the value,which is invalid, must return empty string.");
+
+      test(function() {
+        document.getElementById("invalid_value_is_set").value = "invalid value";
+        assert_equals(document.getElementById("invalid_value_is_set").value, "")
+      }, "When value is set with invalid value, the value must return empty string.");
+
+      test(function() {
+        document.getElementById("step_attribute_is_invalid_value").stepUp();
+        assert_equals(document.getElementById("step_attribute_is_invalid_value").value, "2013-07")
+      }, "When step attribute is given invalid value, it must ignore the invalid value and use defaul value instead.");
+
+      test(function() {
+        assert_equals(document.getElementById("invalid_month_too_high").value, "");
+      }, "Month should be <= 13: 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_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>