Html Code:
<form action="" id="form-1"></form>
<label for="">
First Name:
</label>
<input type="text" name="fname" id="fname" placeholder="">
<label for="">
Last Name:
<input type="text" name="lname" id="lname" placeholder="">
</label>
<button class="btn">Click</button>
<label for="">
Display Full Name:
<input type="text" name="fullName" id="fullName" placeholder="">
</label>
</form>
JS Code:
let form = document.getElementById('form-1');
let fname = document.getElementById('fname').value;
let lname = document.getElementById('lname').value;
form.addEventListener('submit',function(){
document.querySelector('.btn').addEventListener('click',function(){
let display = fname.concat(lname);
document.getElementById('fullName').innerHTML = display;
});
})