web api instance method

HTMLInputElement: checkValidity() method

The checkValidity() method of the HTMLInputElement interface returns a boolean value which indicates if the element meets any constraint validation rules applied to it. If false, the method also fires an invalid event on the element. Because there’s no default browser behavior for checkValidity(), canceling this invalid event has no effect.

[!NOTE] An HTML <input> element with a non-null validationMessage is considered invalid, will match the CSS :invalid pseudo-class, and will cause checkValidity() to return false. Use the setCustomValidity() method to set the validationMessage to the empty string to set the validity state to be valid.

Syntax

checkValidity()

Parameters

None.

Return value

Returns true if the element’s value has no validity problems; otherwise, returns false.

Examples

HTML

We include a form containing a required number field and two buttons: one to check the form and the other to submit it.

<form action="#" method="post">
  <p>
    <label for="age">Your (21 to 65) </label>
    <input type="number" name="age" required id="age" min="21" max="65" />
  </p>
  <p>
    <button type="submit">Submit</button>
    <button type="button" id="check">checkValidity()</button>
  </p>
  <p id="log"></p>
</form>

JavaScript

const output = document.querySelector("#log");
const checkButton = document.querySelector("#check");
const ageInput = document.querySelector("#age");

ageInput.addEventListener("invalid", () => {
  console.log("Invalid event fired.");
});

checkButton.addEventListener("click", () => {
  const checkVal = ageInput.checkValidity();
  output.innerHTML = `checkValidity returned: ${checkVal}`;
});

Results

Interactive exampleOpen the canonical MDN source to run this embedded demo.

When false, if the value is missing, below 21, above 65, or otherwise invalid, the invalid event will be logged to the console. To report the error to the user, use reportValidity() instead.

Specifications

SpecificationsStandards references are available on the canonical MDN page.

Browser compatibility

Browser compatibilityCompatibility data is available on the canonical MDN page.