HTML tutorial
CSS3 tutorial
Bootstrap tutorial
JavaScript tutorial
JQuery tutorial
AngularJS tutorial
React tutorial
NodeJS tutorial
PHP tutorial
Python tutorial
Python3 tutorial
Django tutorial
Linux tutorial
Docker tutorial
Ruby tutorial
Java tutorial
C tutorial
C ++ tutorial
Perl tutorial
JSP tutorial
Lua tutorial
Scala tutorial
Go tutorial
ASP.NET tutorial
C # tutorial
If an input field contains invalid data, display a message
Method/Property | Description |
---|---|
checkValidity() | Returns true if an input element contains valid data. |
setCustomValidity() | Sets the validationMessage property of an input element. |
Property | Description |
validity | Contains boolean properties related to the validity of an input element. |
validationMessage | Contains the message a browser will display when the validity is false. |
willValidate | Indicates if an input element will be validated. |
If an input field contains invalid data, display a message:
<input id="id1" type="number" min="100" max="300"
required>
<button onclick="myFunction()">OK</button>
<p id="demo"></p>
<script>
function myFunction() {
const inpObj = document.getElementById("id1");
if (!inpObj.checkValidity()) {
document.getElementById("demo").innerHTML = inpObj.validationMessage;
}
}
</script>
The validity property of an input element contains a number of properties related to the validity of data:
Property | Description |
---|---|
customError | Set to true, if a custom validity message is set. |
patternMismatch | Set to true, if an element's value does not match its pattern attribute. |
rangeOverflow | Set to true, if an element's value is greater than its max attribute. |
rangeUnderflow | Set to true, if an element's value is less than its min attribute. |
stepMismatch | Set to true, if an element's value is invalid per its step attribute. |
tooLong | Set to true, if an element's value exceeds its maxLength attribute. |
typeMismatch | Set to true, if an element's value is invalid per its type attribute. |
valueMissing | Set to true, if an element (with a required attribute) has no value. |
valid | Set to true, if an element's value is valid. |
If the number in an input field is greater than 100 (the input's max
attribute), display a message:
<input id="id1" type="number" max="100">
<button onclick="myFunction()">OK</button>
<p id="demo"></p>
<script>
function myFunction() {
let text = "Value OK";
if (document.getElementById("id1").validity.rangeOverflow) {
text = "Value too large";
}
}
</script>
If the number in an input field is less than 100 (the input's min
attribute), display a message:
<input id="id1" type="number" min="100">
<button onclick="myFunction()">OK</button>
<p id="demo"></p>
<script>
function myFunction() {
let text = = "Value OK";
if (document.getElementById("id1").validity.rangeUnderflow) {
text = "Value too small";
}
}
</script>