validityState.badInput

The read-only badInput property of a ValidityState object 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. Note: While this is unsupported in Internet Explorer, any non-numeric value will be dismissed from the field if it is a number input.

Example

<input type="number" id="age">

var input = document.getElementById("age");
if (input.validity.badInput) {
  console.log("Bad input detected…");
} else {
  console.log("Content of input ok.");
}

Specifications

Browser compatibility

See also

• Guide: Constraint validation
• Tutorial: Form data validation