Constraint Validation DOM Methods
| Property | Description |
|---|---|
| checkValidity() | Returns true if an input element contains valid data. |
| setCustomValidity() | Sets the validationMessage property of an input element. |
If an input field contains invalid data, display a message:
The checkValidity() Method
<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>