Best settings for HTML <input type="number">, for mobile devices

There is yet another option: <input type="text" inputmode="numeric" pattern="[0-9]*">

Why the GOV.UK Design System team changed the input type for numbers is definitely worth a read.

Note that if you still want to go the <input type="number"> route there is a nice solution to point 4 - Scrolling - Turn Off Number Input Spinners.

Each solution seems to have some drawbacks and I think the best fit will depend on the type of data you're trying to collect, passport number vs someone's age vs number of items.

The drawbacks to this solution that I have found are:

• the input value is now text rather than a number so you may need to do additional parsing in JS.
• on desktop browsers the input will accept alphabetical characters, the form will be invalid but you'll need to handle this and show relevant user feedback (might be automatic if using a framework)
• it's only supported by modern mobile browsers, e.g. Safari on iOS 12.2 (2019 ish) (see spec)

I came across this problem and the following two solutions seem to be the best ways to answer this question

The first solution is very simple and works on both Android and IOS. This solution will have a up and down button on desktop and only a numeric keyboard on both Android and IOS;

<form action="" method="">
<input pattern="[0-9]*"/>
</form>

The only issue with this solution is that, a user will not be able to enter , (commas) or . (periods), since they will not show up on the keyboard. If you alter the pattern, the above will no longer function on IOS.

The second solution is not supported by all browsers, however seems to work on all modern browsers including safari 15.1.

<input inputmode="numeric" pattern="[0-9]*" type="text"/>

To see what browsers support inputmode click here

Good Luck

For your specific task I have the extraordinary solution: we take the best solution with type="text" and pattern and then add the JavaScript which corrects the type attribute. We do it to pass through W3 validator.

The solution

// iOS detection from: stackoverflow.com/a/9039885 with explanation about MSStream
if(/iPad|iPhone|iPod/.test(navigator.userAgent) && !window.MSStream)
{
    var inputs = document.querySelectorAll('input[type="number"]');
    for(var i = inputs.length; i--;)
        inputs[i].setAttribute('pattern', '\\d*');
}

<input type="number" />

My solution respects all your three rules (W3 validator inclusive).

But I have to mention that in this case(with pattern) on iOS we do not have the possibility to put float numbers with numeric keypad because on iOS we do not have any keypad with numbers including points. On Android we have this possibility. If you want to have numeric keypad with float numbers then you have to write for iOS extra solution like follows:

 <input type="number" />

As mentioned in the comments, because there is no straight forward way to accomplish this, the best work around is to always use an input type="number" with an if statement that if the device is an iOS device then the code will add the proper pattern attribute to the type.