如何将两个变量与 Javascript 结合起来？

Question

I have a form that collects first name and last name via two div elements:

<div class="form-row">
  <div class="col">
    <input type="text" class="form-control" id="lastName" placeholder="last name" />
  </div>
</div>

<div class="form-row">
  <div class="col">
    <input type="text" class="form-control" id="firstname" placeholder="first name" />
  </div>
</div>

In the script I have the following line

const lastName = document.getElementById('lastName').value;

What I would like to do is produce a constant called fullname which comprises of firstname+lastname

How can I rewrite the line starting with const above to do this?

Answer 1

This one should be fairly simply. You already have a way of extracting the value of the lastName input. So just do the same for firstName and then concatenate the two variables.

const firstName = document.getElementById('firstName').value;
const lastName = document.getElementById('lastName').value;

const fullName = `${firstName} ${lastName}`;

Answer 2

Using your existing syntax:

const fullName = document.getElementById('firstname').value + ' ' + document.getElementById('lastName').value;

There are of course other ways to get these values and this assumes there will be a value but you get the gist.