ValidityState: stepMismatch property

Baseline Widely available

This feature is well established and works across many devices and browser versions. It’s been available across browsers since July 2015.

See full compatibility

The read-only stepMismatch property of the ValidityState interface indicates if the value of an <input>, after having been edited by the user, does not conform to the constraints set by the element's step attribute.

If the field is numeric in nature, including the date, month, week, time, datetime-local, number and range types and the step value is not any, if the value don't doesn't conform to the constraints set by the step and min values, then stepMismatch will be true. If the remainder of the form control's value less the min value, divided by the step value (which defaults to 1 if omitted) is not zero, there is a mismatch.

Value

A boolean that is true if the ValidityState does not conform to the constraints.

Examples

Input with step mismatch

The following example checks the validity of a numeric input element. A constraint has been added using the step attribute which means the input expects increments of 5 as values. If the user enters a number that's not divisible by 5, the element fails constraint validation, and the styles matching :invalid CSS pseudo-class are applied.

css

input:invalid {
  outline: red solid 3px;
}

body {
  margin: 0.5rem;
}
pre {
  padding: 1rem;
  height: 2rem;
  background-color: lightgrey;
  outline: 1px solid grey;
}

html

<pre id="log">Validation logged here...</pre>
<input type="number" id="degrees" step="5" />

const userInput = document.getElementById("degrees");
const logElement = document.getElementById("log");

function log(text) {
  logElement.innerText = text;
}

userInput.addEventListener("input", () => {
  userInput.reportValidity();
  if (userInput.validity.stepMismatch) {
    log("Input must be divisible by 5");
  } else {
    log("Input is valid…");
  }
});

Specifications

Specification
HTML # dom-validitystate-stepmismatch

Browser compatibility

	desktop					mobile
	Chrome	Edge	Firefox	Opera	Safari	Chrome Android	Firefox for Android	Opera Android	Safari on iOS	Samsung Internet	WebView Android	WebView on iOS
`stepMismatch`	Chrome – Full support Chrome 4 (Release date: 2010-01-25) footnote Full support	Edge – Full support Edge 12 (Release date: 2015-07-29) footnote Full support	Firefox – Full support Firefox 4 (Release date: 2011-03-22) footnote Full support	Opera – Full support Opera 12.1 (Release date: 2012-11-20) footnote Full support	Safari – Full support Safari 5 (Release date: 2010-06-07) footnote Full support	Chrome Android – Full support Chrome Android 18 (Release date: 2012-06-27) footnote Full support	Firefox for Android – Full support Firefox for Android 4 (Release date: 2011-03-29) footnote Full support	Opera Android – Full support Opera Android 12.1 (Release date: 2012-10-09) footnote Full support	Safari on iOS – Full support Safari on iOS 5 (Release date: 2011-10-12) footnote Full support	Samsung Internet – Full support Samsung Internet 1 (Release date: 2013-04-27) footnote Full support	WebView Android – Full support WebView Android 4.4 (Release date: 2013-12-09) footnote Full support	WebView on iOS – Full support WebView on iOS 5 (Release date: 2011-10-12) footnote Full support

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Full support: Full support