2021-02-16 Click Highlighter

Click highlighter with CSS transitions

by Ttt Yyy

HTML

<h1>Click somewhere</h1>
<p>Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.</p>
<p>Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.</p>
<p>Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.</p>
<p>Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.</p>
<p>Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam,...

CSS

#lookatmeiamhere {
    cursor: pointer;
    background: rgba(255, 255, 10, 0.7);
    width: 100px;
    height: 100px;
    position: absolute;
    border-radius: 100px;
    -webkit-transition: -webkit-transform 1s;
    -moz-transition: -moz-transform 1s;
    -ms-transition: -ms-transform 1s;
    -o-transition: -o-transform 1s;
    transition: transform 1s;
    -webkit-transform: scale(0, 0);
    -moz-transform: scale(0, 0);
    -ms-transform: scale(0, 0);
    -o-transform: scale(0, 0);
    transform: scale(0, 0);
  }

  .down #lookatmeiamhere {
    -webkit-transform: scale(1, 1);
    -moz-transform: scale(1, 1);
    -ms-transform: scale(1, 1);
    -o-transform: scale(1, 1);
    transform: scale(1, 1);
  }

JavaScript

// create a DIV element, give it an ID and add it
const plot = document.createElement('div');
let pressed = false;
plot.id = 'lookatmeiamhere';
document.body.appendChild(plot);

// define offset as half the width of div; puts mouse in center
const offset = plot.offsetWidth / 2;

function moveplot( x, y ) {
  plot.style.left = x - offset + 'px';
  plot.style.top = y - offset + 'px';
}

document.addEventListener( 'mousedown', function(ev) {
  document.body.classList.add('down');
  pressed = true;
  moveplot( ev.pageX, ev.pageY );
}, false );

document.addEventListener( 'mouseup', function(ev) {
  document.body.classList.remove('down');
  pressed = false;
},  false );

document.addEventListener( 'mousemove', function(ev) {
  if (pressed) { moveplot( ev.pageX, ev.pageY ); }
}, false );

// https://hacks.mozilla.org/2012/04/click-highlights-with-css-transitions/
/* (function(){
var plot = document.createElement('div'),
    pressed = false;
plot.id = 'lookatmeiamhere';
document.body.appendChild(plot);
var offset = plot.offsetWidth / 2;
document.addEventListener( 'mousedown', function(ev) {
  document.body.classList.add('down');
  pressed = true;
  moveplot( ev.pageX, ev.pageY );
}, false );
document.addEventListener( 'mouseup', function(ev) {
  document.body.classList.remove('down');
  pressed = false;
},  false );
function moveplot( x, y ) {
  plot.style.left = x - offset + 'px';
  plot.style.top = y - offset + 'px';
}
document.addEventListener( 'mousemove', function(ev) {
  if (pressed) { moveplot( ev.pageX, ev.pageY ); }
}, false );
 })(); */