<!DOCTYPE html>
<html>
<head>
<title>Form Validation</title>
</head>
<body>
<form onsubmit="return validateForm()">
<label for="age">Age:</label>
<input type="text" id="age" name="age">
<input type="submit" value="Submit">
</form>
<p id="error"></p>
<script>
function validateForm() { let age = document.getElementById("age").value; if (isNaN(age) || age < 0 || age > 120) { document.getElementById("error").textContent = "Please enter a valid age."; return false;
}
return true;
}
</script>
</body>
</html>
