ValidityState: badInput property

Baseline Widely available

This feature is well established and works across many devices and browser versions. It’s been available across browsers since December 2018.

See full compatibility

The read-only badInput property of the ValidityState interface indicates if the user has provided input that the browser is unable to convert. For example, if you have a number input element whose content is a string.

Value

A boolean that is true if the ValidityState object does not conform to the expected type.

Examples

Detecting bad input

The following example checks the validity of a numeric input element. If the user enters text instead of a number, the element fails constraint validation, and the styles matching input:invalid are applied. The <pre> element above the input shows the validation message when the element badInput evaluates to true:

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="age" />

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

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

userInput.addEventListener("input", () => {
  userInput.reportValidity();
  if (userInput.validity.badInput) {
    log(`Bad input detected: ${userInput.validationMessage}`);
  }
});

Specifications

Specification
HTML # dom-validitystate-badinput-dev

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
`badInput`	Chrome – Full support Chrome 25 (Release date: 2013-02-21) footnote Full support	Edge – Full support Edge 12 (Release date: 2015-07-29) footnote Full support	Firefox – Full support Firefox 29 (Release date: 2014-04-29) footnote Full support	Opera – Full support Opera 15 (Release date: 2013-07-02) footnote Full support	Safari – Full support Safari 7 (Release date: 2013-10-22) footnote Full support	Chrome Android – Full support Chrome Android 25 (Release date: 2013-02-27) footnote Full support	Firefox for Android – Full support Firefox for Android 64 (Release date: 2018-12-11) footnote Full support	Opera Android – Full support Opera Android 14 (Release date: 2013-05-21) footnote Full support	Safari on iOS – Full support Safari on iOS 7 (Release date: 2013-09-18) footnote Full support	Samsung Internet – Full support Samsung Internet 1.5 (Release date: 2013-09-25) 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 7 (Release date: 2013-09-18) footnote Full support

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Full support: Full support