subimage shows when mainimage is clicked

Stackoverflow solution

by Atif Hassan

HTML

<img id="toggle" src="https://s19.postimg.org/an381cz4j/470766057_3f1e9a3933_b.jpg" alt="jungle" width="75vw" height="50vw" onclick="toggle_img()" />

<img id="toggle_image" src="https://s19.postimg.org/klo6nu8k3/sumatrantiger-002.jpg" alt="tiger" width="75vw" height="50vw" onclick="toggle_img()" style="opacity:0"/>

JavaScript

var toggle = false;

function toggle_img() {
  if (toggle) {
    document.getElementById("toggle_image").style.opacity = 0;
    toggle = false;
  } else {
    document.getElementById("toggle_image").style.opacity = 1;
    toggle = true;
  }
}