Changing background color based on cursor position

cursor_background-change.js

// background color change according to cursor position
$(document).mousemove(function (e) {

  var $width = ($(document).width()) / 255;
  var $height = ($(document).height()) / 255;
  var $pageX = parseInt(e.pageX / $width, 10);
  var $pageY = parseInt(e.pageY / $height, 10);

  // rgba($a-$b-$c);
  var $a = $pageX,
      $b = ($pageY - 255) * (-1),
      $c = 0;

  // if cursor is in bottom left, adjust $c accordingly
  if ($pageX <= $pageY) {
      $c = $pageY - $pageX;
  }

  // change element to whatever you need to target
  $(element).css('background-color', 'rgb('+$a+','+$b+','+$c+')');

});