HTMLObjectElement.setCustomValidity - Web APIs 编辑

The setCustomValidity() method of the HTMLObjectElement interface sets a custom validity message for the element.

Syntax

HTMLObjectElement.setCustomValidity(message);

Parameters

error

The message to use for validity errors.

Return value

undefined

Exceptions

None.

Examples

In this example, we pass the ID of an input element, and set different error messages depending on whether the value is missing, too low or too high. Additionally you must call the reportValidity method on the same element or nothing will happen.

function validate(inputID)
{
 var input = document.getElementById(inputID);
 var validityState_object = input.validity;

 if (validityState_object.valueMissing)
 {
  input.setCustomValidity('You gotta fill this out, yo!');
  input.reportValidity();
 }
 else if (validityState_object.rangeUnderflow)
 {
  input.setCustomValidity('We need a higher number!');
  input.reportValidity();
 }
 else if (validityState_object.rangeOverflow)
 {
  input.setCustomValidity('Thats too high!');
  input.reportValidity();
 }
 else
 {
  input.setCustomValidity('');
  input.reportValidity();
 }
}

It's vital to set the message to an empty string if there are no errors. As long as the error message is not null, the form will not pass validation and will not be submitted.

Specifications

Browser compatibility

BCD tables only load in the browser

See also

• validityState
• validityState.valueMissing
• validityState.typeMismatch
• validityState.patternMismatch
• validityState.tooLong
• validityState.tooShort
• validityState.rangeUnderflow
• validityState.rangeOverflow
• validityState.stepMismatch
• validityState.valid
• validityState.customError