Modal Onclick Visibility Not Working As Intended

Issue

My modal below isn't working but I'm not experienced enough to figure why. I'm trying to hide my modal using visibility: hidden, then changing to visibility: visible onclick.

HTML

    <div class="modalSignin"></div>

     <div class="authBtns" onclick="modalLogin()">
          <a href="#" id="loginBtn">Login</a>
          <a href="#" id="regBtn">Register</a>
     </div>

CSS:

    .modalSignin {
        position: absolute;
        top: 50%;
        left: 50%;
        transform: translate(-50%, -50%);
        background-color: black;
        min-width: 40%;
        min-height: 400px;
        visibility: hidden;
    }

JAVASCRIPT:

   function modalLogin() {
        var modal = document.getElementsByClassName("modalSignin");
         modal.style.visibility = "visible";
    };

Please see above code snippets.

Solution

document.getElementsByClassName

The above returns a collection (an array of results, note the plural on getElement(s)). So you can't just set the visibility directly on it.

Just by simply changing it to access the first index, it will work

function modalLogin() {
    var modal = document.getElementsByClassName("modalSignin")[0];
    modal.style.visibility = "visible";
}

But it would have been better if you used an ID instead, and access it by ID, which returns the same results.

function modalLogin() {
  var modal = document.getElementById("sign_in_modal");
  modal.style.visibility = "visible";
}

Full snippet below.

function modalLogin() {
  var modal = document.getElementById("sign_in_modal");
  modal.style.visibility = "visible";
}

.modalSignin {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  background-color: black;
  min-width: 40%;
  min-height: 400px;
  visibility: hidden;
}

<div class="modalSignin" id="sign_in_modal"></div>

<div class="authBtns" onclick="modalLogin()">
  <a href="#" id="loginBtn">Login</a>
  <a href="#" id="regBtn">Register</a>
</div>

Answered By - Patrick Teng