问为上次单击的按钮和访问过的按钮未访问的按钮分开颜色

EN

.visited-button{
   background-color: #342762; /*visited color*/
}

.normal-button{
   background-color: #ff76aa; /*non-visited color*/
}

// your function
    var btn = document.createElement("BUTTON");
    btn.style.backgroundColor = "D3D578";
    btn.setAttribute("id", "btn" + buttonId);
    btn.setAttribute("class", "class" + classId);

 // Add this here
    btn.onclick=changeButtonColor(btn);

    btn.innerText = "click" + buttonId;
    btn.innerText = "click" + classId;
    console.log(btn);
    document.body.appendChild(btn);buttonId++;classId++;
// end of your function


function changeButtonColor(button){
   button.class = "visited-button";
}

function generateButtons(totalBtns){
	for(var i=0; i<totalBtns; i++){
  	var btn = document.createElement("button");
    btn.setAttribute("class", "unvisited-color");
    btn.innerText = "clickbtn" + i;
    btn.addEventListener('click', onBtnClick);
    document.body.appendChild(btn);
  } 
}
function onBtnClick(event){
	event.target.setAttribute("class", "visited-color");
}
generateButtons(3); //generate buttons dynamically

.unvisited-color{
  background-color:#D3D578;
}

.visited-color{
  background-color:#E5E5E5;
}