JSFiddle - React, Tailwind, and code Playground

by Alexandru Gatea

HTML

<div id="main-container">
  <div id="navBtn"></div>
  <div id="container">
    <div id="navMenu"></div>
  </div>
</div>

CSS

#main-container {
  width: 350px;
  height: 600px;
  border: 1px solid black;
  position: absolute;
  overflow: hidden;
}

#container {
  width: 350px;
  height: 100%;
  z-index: 1;
  background: rgba(0, 102, 199, 0.8);
  transition: all 0.3s ease-in-out;
}

#navBtn {
  width: 50px;
  height: 50px;
  background: red;
  position: absolute;
  z-index: 999;
}

#navMenu {
  width: 250px;
  height: 100%;
  background: blue;
  position: absolute;
  z-index: 9999;
  top: 0;
  left: -250px;
  transition: all 0.3s ease-in-out;
}

#container.open  {
  background: rgba(0, 102, 199,1);
}


#container.open #navMenu {
  left: 0;
}

JavaScript

var navBtn = document.getElementById("navBtn");
var navMenu = document.getElementById("navMenu");
var container = document.getElementById("container");
navBtn.addEventListener("click", showMenu);
container.addEventListener("click", hideMenu);

//navMenu.style.display = "none"; // remove the display: none as you cannot animate display block to display none

function showMenu() {
	container.classList.add('open');
}

function hideMenu() {
  container.classList.remove('open');
}