JS: jQuery event.preventDefault()
event.preventDefault():
Use to stop action, ex: submit form, link from URL
<!DOCTYPE html>
<html>
<body>
<form action="#">
<label for="fname">First name: </label>
<input id="fname" type="text">
<label for="lname">Last name: </label>
<input id="lname" type="text">
<input id="submit" type="submit">
<div></div>
</form>
<script>
var form = document.querySelector('form');
var fname = document.getElementById('fname');
var lname = document.getElementById('lname');
var submit = document.getElementById('submit');
var message = document.querySelector('div');
form.addEventListener('submit', function(e) {
if (fname.value === '' || lname.value === '') {
//e.preventDefault();
message.innerHTML = 'You need to fill in both names!';
}
});
</script>
</body>
</html>