JSFiddle - React, Tailwind, and code Playground
JavaScript
var p = new Raphael(10,10, 500, 500);
var x = 0.5;
var r = p.rect(20, 20, 100, 80, 5).attr({fill: 'red', opacity: x}),
c = p.circle(200, 200, 80).attr({fill: 'orange'}),
s = p.set(r, c);
s.click(function() {
s[0].attr({opacity: x - 0.3});
s[1].attr({opacity: 0.3});
});