javascript - 鼠标悬停 mouseout JavaScript 不工作

Question

我试图让一个元素在客户的鼠标悬停在它上面时出现，并在它离开对象时消失，但它不起作用。这是非常简单的代码，我不明白为什么它不起作用。这是代码:

var earlyBirds = document.getElementById("earlyBirds");
var block = document.getElementById("block");

var appearenceEB = function(){
    block.style.visibility = visible;
}

var dissappearenceEB = function(){
    block.style.visibility = hidden;   
}

earlyBirds.addEventListener("mouseover", appearenceEB);
earlyBirds.addEventListener("mouseout", dissappearenceEB);

Answer 1

visible 和 hidden 应该用引号引起来。

var appearenceEB = function(){
    block.style.visibility = "visible";
}

var dissappearenceEB = function(){
    block.style.visibility = "hidden";   
}