<input type="week">

<input> elements of type "week" create input fields allowing easy entry of a year plus the number of the week during that year (e.g. week 1 to 52).

The control's user interface varies from browser to browser; cross-browser support is currently a bit limited, with only Chrome/Opera and Microsoft Edge supporting it at this time. In non-supporting browsers, the control degrades gracefully to function identically to <input type="text">.

<input id="week" type="week">

In Chrome/Opera the week control provides slots to fill in week and year values, a pop-up calendar interface to select them more visually, and an "X" button to clear the control's value.

The Edge week control is somewhat more elaborate, opening up week and year pickers with sliding reels.

Value

A DOMString representing the value of the week/year entered into the input. You can set a default value for the input by including a value inside the value attribute, like so:

<label for="week">What week would you like to start?</label>
<input id="week" type="week" name="week" value="2017-W01">

One thing to note is that the displayed format may differ from the actual value, which is always formatted yyyy-Www. When the above value is submitted to the server, for example, browsers may display it as Week 01, 2017, but the submitted value will always look like week=2017-W01.

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

var weekControl = document.querySelector('input[type="week"]');
weekControl.value = '2017-W45';

Using week inputs

Week inputs sound convenient at first glance, since they provide an easy UI for choosing weeks, and they normalize the data format sent to the server, regardless of the user's browser or locale. However, there are issues with <input type="week"> because browser support is not guaranteed across all browsers.

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

Basic uses of week

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

<form>
  <label for="week">What week would you like to start?</label>
  <input id="week" type="week" name="week">
</form>

Controlling input size

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

Using the step attribute

You should be able to use the step attribute to vary the number of weeks jumped whenever they are incremented or decremented, however it doesn't seem to have any effect on supporting browsers.

Validation

By default, <input type="week"> does not apply any validation to entered values. The UI implementations generally don't let you specify anything that isn't a valid week/year, which is helpful, but it's still possible to submit with the field empty, and you might want to restrict the range of choosable weeks.

Setting maximum and minimum weeks

You can use the min and max attributes to restrict the valid weeks that can be chosen by the user. In the following example we are setting a minimum value of Week 01, 2017 and a maximum value of Week 52, 2017:

<form>
  <label for="week">What week would you like to start?</label>
  <input id="week" type="week" name="week"
         min="2017-W01" max="2017-W52">
  <span class="validity"></span>
</form>

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;
}

The result here is that only weeks between W01 and W52 in 2017 will be seen as valid and be selectable in supporting browsers.

Making week values required

In addition you can use the required attribute to make filling in the week mandatory. As a result, supporting browsers will display an error if you try to submit an empty week field.

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

<form>
  <div>
    <label for="week">What week would you like to start?</label>
    <input id="week" type="week" name="week"
         min="2017-W01" max="2017-W52" required>
    <span class="validity"></span> 
  </div>
  <div>
      <input type="submit" value="Submit form">
  </div>
</form>

If you try to submit the form with no value, 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:

Handling browser support

As mentioned above, the major problem with using week inputs right now is browser support: Safari and Firefox don't support it on desktop, and old versions of IE don't support it.

Mobile platforms such as Android and iOS make really good use of such input types, providing specialist UI controls that make it really easy to select values in a touchscreen environment. For example, the week 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. As mentioned earlier, with a week input the actual value is always normalized to the format yyyy-Www. When the browser falls back to a generic text input, there's nothing to guide the user toward correctly formatting the input (and it's certainly not intuitive). There are multiple ways in which people could write week values; for example:

• Week 1 2017
• Jan 2-8 2017
• 2017-W01
• etc.

The best way to deal with week/years in forms in a cross-browser way at the moment is to get the user to enter the week number and year in separate controls (<select> elements being popular; see below for an example), or use JavaScript libraries such as jQuery date picker.

Examples

In this example we create two sets of UI elements for choosing weeks: a native picker created using <input type="week">, and a set of two <select> elements for choosing weeks/years in older browsers that don't support the week input type.

The HTML looks like so:

<form>
  <div class="nativeWeekPicker">
    <label for="week">What week would you like to start?</label>
    <input id="week" type="week" name="week"
           min="2017-W01" max="2018-W52" required>
    <span class="validity"></span>
  </div>
  <p class="fallbackLabel">What week would you like to start?</p>
  <div class="fallbackWeekPicker">
    <div>
      <span>
        <label for="week">Week:</label>
        <select id="fallbackWeek" name="week">
        </select>
      </span>
      <span>
        <label for="year">Year:</label>
        <select id="year" name="year">
          <option value="2017" selected>2017</option>
          <option value="2018">2018</option>
        </select>
      </span>
    </div>
  </div>
</form>

The week values are dynamically generated by the JavaScript code below.

The other part of the code that may be of interest is the feature detection code. To detect whether the browser supports <input type="week">, we create a new <input> element, set its type to week, then immediately check what its type is set to. Non-supporting browsers will return text, because the week type falls back to type text. If <input type="week"> is not supported, we hide the native picker and show the fallback picker UI (<select>s) instead.

// define variables
var nativePicker = document.querySelector('.nativeWeekPicker');
var fallbackPicker = document.querySelector('.fallbackWeekPicker');
var fallbackLabel = document.querySelector('.fallbackLabel');

var yearSelect = document.querySelector('#year');
var weekSelect = document.querySelector('#fallbackWeek');

// 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 = 'week';
// 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 weeks dynamically
  populateWeeks();
}

function populateWeeks() {
  // Populate the week select with 52 weeks
  for(var i = 1; i <= 52; i++) {
    var option = document.createElement('option');
    option.textContent = (i < 10) ? ("0" + i) : i;
    weekSelect.appendChild(option);
  }
}

Specifications

Browser compatibility

[1] This feature is not implemented yet. See bug 888320 and TPE DOM/Date time input types.

See also

• The generic <input> element and the interface used to manipulate it, HTMLInputElement
• <input type="datetime-local">, <input type="date">, <input type="time">, and <input type="month">