function show(ev) {
    var element = (ev.target||ev.srcElement);
    element.style.backgroundColor = "white";
}

function addAll(){
var item;  
    var checks = document.getElementsByTagName("span");  
    for (item of checks){
	if (item.getAttribute("class") == "check"){
	    item.addEventListener("click", show, false);    
	}
    }
}
window.onload = addAll;

bubbly({
  colorStart: '#fff4e6',
  colorStop: '#ffe9e4',
  blur:1,
  compose: 'source-over',
  bubbleFunc:() => `hsla(${Math.random() * 50}, 100%, 50%, .3)`
});