HTMLTextAreaElement: setCustomValidity() method
The setCustomValidity() method of the HTMLTextAreaElement interface sets the custom validity message for the <textarea> element. Use the empty string to indicate that the element does not have a custom validity error.
Syntax
js
setCustomValidity(string)
Parameters
string-
The string containing the error message. The empty string removes any custom validity errors.
Return value
None (undefined).
Examples
In this example, if the <textarea>'s doesn't pass constraint validation, we provide custom errors based on the constraint that is failing validation. If the value is valid, we set the custom error to an empty string:
js
const comment = document.getElementById("comment");
if (comment.validity.valueMissing) {
comment.setCustomValidity("We can't submit a blank comment!");
} else if (comment.validity.tooShort) {
comment.setCustomValidity("Tell us more! Your comment is too short.");
} else if (comment.validity.tooLong) {
comment.setCustomValidity(
"Loquacious much? Keep it to under 800 characters!",
);
} else {
comment.setCustomValidity("");
}