この翻訳は不完全です。英語から この記事を翻訳 してください。

<input> elements of type month create input fields that let the user enter a month and year allowing a month and year to be easily entered. The value is a string whose value is in the format "YYYY-MM", where YYYY is the four-digit year and MM is the month number.

The control's UI varies in general from browser to browser; at the moment support is patchy, with only Chrome/Opera and Edge on desktop — and most modern mobile browser versions — having usable implementations. In browsers that don't support month inputs, the control degrades gracefully to a simple <input type="text">, although there may be automatic validation of the entered text to ensure it's formatted as expected.

For those of you using a browser that doesn't support month, the screenshot below shows what it looks like in Chrome and Opera. Clicking the down arrow on the right hand side brings up a date picker that lets you select the month and year.

The Microsoft Edge month control looks like this:

年と月を表現する DOMString、または空欄
イベント change および input
対応する共通属性 autocomplete, list, readonly, step
IDL 属性 value
メソッド select(), stepDown(), stepUp()

A DOMString representing the value of the month and year entered into the input, in the form YYYY-MM (four digit year, then a hyphen ("-"), followed by the two-digit month. You can set a default value for the input control by including a month and year inside the value attribute, like so:

<label for="bday-month">What month were you born in?</label>
<input id="bday-month" type="month" name="bday-month" value="2017-06">

One thing to note is that the displayed date format differs from the actual value; most user agents display the month and year in a locale-appropriate form, based on the set locale of the user's operating system, whereas the date value is always formatted yyyy-MM.

When the above value is submitted to the server, for example, it will look like bday-month=1978-06.

You can also get and set the date value in JavaScript using the HTMLInputElement.value property, for example:

var monthControl = document.querySelector('input[type="month"]');
monthControl.value = '1978-06';

月入力の使用

Date-related inputs (including month) sound convenient at first glance; they promise an easy UI for choosing dates, and they normalize the data format sent to the server, regardless of the user's locale. However, there are issues with <input type="month"> because at this time, many major browsers don't yet support it.

We'll look at basic and more complex uses of <input type="month">, then offer advice on mitigating the browser support issue in the section Handling browser support).

月入力の基本的な使用

The simplest use of <input type="month"> involves a basic <input> and <label> element combination, as seen below:

<form>
  <label for="bday-month">What month were you born in?</label>
  <input id="bday-month" type="month" name="bday-month">
</form>

Setting maximum and minimum dates

You can use the min and max attributes to restrict the range of dates that the user can choose. In the following example we specify a minimum month of 1900-01 and a maximum month of 1999-12:

<form>
  <label for="bday-month">What month were you born in?</label>
  <input id="bday-month" type="month" name="bday-month"
         min="1900-01" max="1999-12">
</form>

The result here is that:

  • Only months between in January 1900 and December 1999 can be selected; months outside that range can't be scrolled to in the control.
  • Depending on what browser you are using, you might find that months outside the specified range might not be selectable in the month picker (e.g. Edge), or invalid (see Validation) but still available (e.g. Chrome).

入力欄の寸法の制御

<input type="month"> doesn't support form sizing attributes such as size. You'll have to resort to CSS for sizing needs.

検証

既定で、 <input type="month"> は入力された値の検証を行いません。ユーザーインターフェイスの実装は一般的に、日付でないものの入力をさせないからです。これは便利です。しかし、それでも month 入力欄を空のまま、または無効な日付 (例えば4月32日など) を入力してフォームを送信することが可能です。

To help avoid this, you can use min and max to restrict the available dates (see anch("Setting maximum and minimum dates")), and in addition use the required attribute to make filling in the date mandatory. As a result, supporting browsers will display an error if you try to submit a date that is outside the set bounds, or an empty date field.

Let's look at an example; here we've set minimum and maximum dates, and also made the field required:

<form>
  <div>
    <label for="month">What month would you like to visit us (Summer months only, please)?</label>
    <input id="month" type="month" name="month"
           min="2017-06" max="2017-09" required>
    <span class="validity"></span>
  </div>
  <div>
      <input type="submit" value="Submit form">
  </div>
</form>

If you try to submit the form without both the month and year specified (or with a date outside the set bounds), the browser displays an error. Try playing with the example now:

Here's a screenshot for those of you who aren't using a supporting browser:

Here's the CSS used in the above example. Here we make use of the :valid and :invalid CSS properties to style the input based on whether or not the current value is valid. We had to put the icons on a <span> next to the input, not on the input itself, because in Chrome the generated content is placed inside the form control, and can't be styled or shown effectively.

div {
  margin-bottom: 10px;
  position: relative;
}

input[type="number"] {
  width: 100px;
}

input + span {
  padding-right: 30px;
}

input:invalid+span:after {
  position: absolute;
  content: '✖';
  padding-left: 5px;
}

input:valid+span:after {
  position: absolute;
  content: '✓';
  padding-left: 5px;
}

重要: HTML のフォーム検証は、入力されたデータが正しい形式であることを保証するスクリプトの代用にはなりません。 HTML を調整して検証をくぐり抜けたり、完全に削除したりすることはとても簡単にできます。 HTML を完全にバイパスし、サーバーに直接データを送信することも可能です。サーバー側のコードが受信したデータの検証に失敗した場合、不適切な形式のデータ (または大きすぎるデータ、誤った種類のデータなど) が送信された場合に障害が発生するおそれがあります。

ブラウザーの対応の扱い

As mentioned above, the major problem with using date inputs at the time of writing is that many major browsers don't yet implement them all; only Chrome/Opera and Edge support it on desktop, and most modern browsers on mobile. As an example, the month picker on Chrome for Android looks like this:

Non-supporting browsers gracefully degrade to a text input, but this creates problems both in terms of consistency of user interface (the presented control will be different), and data handling.

The second problem is the more serious of the two. As mentioned earlier, with a month input the actual value is always normalized to the format yyyy-mm. On the other hand, in its default configuration, a text input has no idea what format the date should be in, and this is an issue because of the number of different ways in which people write dates. For example:

  • mmyyyy (072018)
  • mm/yyyy (07/2018)
  • mm-yyyy (07-2018)
  • yyyy-mm (2018-07)
  • Month yyyy (July 2018)
  • ... and so forth.

One way around this is to put a pattern attribute on your month input. Even though the month input doesn't use it, if the browser falls back to treating it like a text input, the pattern will be used. For example, try viewing the following demo in a browser that doesn't support month inputs:

<form>
  <div>
    <label for="month">What month would you like to visit us? (Summer months only, yyyy-mm)</label>
    <input id="month" type="month" name="month"
           min="2017-06" max="2017-09" required
           pattern="[0-9]{4}-[0-9]{2}">
    <span class="validity"></span>
  </div>
  <div>
      <input type="submit" value="Submit form">
  </div>
</form>

If you try submitting it, you'll see that the browser now displays an error message (and highlights the input as invalid) if your entry doesn't match the pattern nnnn-nn, where n is a number from 0 to 9. Of course, this doesn't stop people from entering invalid dates (such as "0000-42"), or incorrectly formatted dates that follow the pattern.

There's also the problem that the user won't necessarily know which of the many date formats is expected. We have work left to do.

The best way to deal with dates in forms in a cross-browser way (until all of the major browsers have supported them for a while) is to get the user to enter the month and year in separate controls (<select> elements being popular; see below for an implementation), or use JavaScript libraries such as the jQuery date picker plugin.

Examples

In this example, we create two sets of UI elements, each designed to let the user select a month and year. The first is a native month input, and the other is a pair of <select> elements that allow choosing a month and year independently, for compatibility with browsers that don't yet support <input type="month">.

HTML

The form that requests the month and year looks like this:

<form>
  <div class="nativeDatePicker">
    <label for="month-visit">What month would you like to visit us?</label>
    <input type="month" id="month-visit" name="month-visit">
    <span class="validity"></span>
  </div>
  <p class="fallbackLabel">What month would you like to visit us?</p>
  <div class="fallbackDatePicker">
    <div>
      <span>
        <label for="month">Month:</label>
        <select id="month" name="month">
          <option selected>January</option>
          <option>February</option>
          <option>March</option>
          <option>April</option>
          <option>May</option>
          <option>June</option>
          <option>July</option>
          <option>August</option>
          <option>September</option>
          <option>October</option>
          <option>November</option>
          <option>December</option>
        </select>
      </span>
      <span>
        <label for="year">Year:</label>
        <select id="year" name="year">
        </select>
      </span>
    </div>
  </div>
</form>

The <div> with the ID "nativeDatePicker" uses the month input type to request the month and year, while the <div> with the ID "fallbackDatePicker" instead uses a pair of <select> elements. The first requests the month, and the second the year.

The <select> for choosing the month is hardcoded with the names of the months, as they don't change (leaving localization out of things). The list of available year values is dynamically generated depending on the current year (see the code comments below for detailed explanations of how these functions work).

The other part of the example that may be of interest is the feature detection code. In order to detect whether the browser supports <input type="month">, we create a new <input> element, set its type to month, then immediately check what its type is set to. Browsers that don't support type month will return text, since that's What month falls back to when not supported. If <input type="month"> is not supported, we hide the native picker and show the fallback picker UI instead.

JavaScript

The JavaScript code that handles selecting which approach to use and to set up the list of years to include in the non-native year <select> follows:

// define variables
var nativePicker = document.querySelector('.nativeDatePicker');
var fallbackPicker = document.querySelector('.fallbackDatePicker');
var fallbackLabel = document.querySelector('.fallbackLabel');

var yearSelect = document.querySelector('#year');
var monthSelect = document.querySelector('#month');

// hide fallback initially
fallbackPicker.style.display = 'none';
fallbackLabel.style.display = 'none';

// test whether a new date input falls back to a text input or not
var test = document.createElement('input');
test.type = 'month';
// if it does, run the code inside the if() {} block
if(test.type === 'text') {
  // hide the native picker and show the fallback
  nativePicker.style.display = 'none';
  fallbackPicker.style.display = 'block';
  fallbackLabel.style.display = 'block';

  // populate the years dynamically
  // (the months are always the same, therefore hardcoded)
  populateYears();
}

function populateYears() {
  // get the current year as a number
  var date = new Date();
  var year = date.getFullYear();

  // Make this year, and the 100 years before it available in the year <select>
  for(var i = 0; i <= 100; i++) {
    var option = document.createElement('option');
    option.textContent = year-i;
    yearSelect.appendChild(option);
  }
}

メモ: 53週ある年もあることを忘れないでください(年あたりの週数を参照)。商品のアプリを開発するときはこれを念頭に置いておく必要があります。

仕様書

仕様書 状態 備考
HTML Living Standard
<input type="month"> の定義
現行の標準  

ブラウザーの対応

機能ChromeEdgeFirefoxInternet ExplorerOperaSafari
基本対応2012 なし1 なし11 なし2
機能Android webviewChrome for AndroidEdge mobileFirefox for AndroidOpera AndroidiOS SafariSamsung Internet
基本対応 あり あり ? なし あり あり ?

1. See bug 888320.

2. The input type is recognized, but there is no month-specific control.

関連情報

ドキュメントのタグと貢献者

このページの貢献者: mfuji09, silverskyvicto
最終更新者: mfuji09,