javascript - 悬停在一个元素上更改另一个元素的背景图像

Question

我尝试使用 javascript 通过将鼠标悬停在 上来更改背景 img。

但 javascript 只适用于第一个

document.getElementById("a").addEventListener("mouseover", function() {
    document.getElementById("bg").style.backgroundImage = "url(https://www.gravatar.com/avatar/9385da4a3618cdc385bd49fe3d951b78?s=32&d=identicon&r=PG)";
}, false);
document.getElementById("a").addEventListener("mouseout", function() {
    document.getElementById("bg").style.backgroundImage = "";
}, false);

document.getElementById("b").addEventListener("mouseover", function() {
    document.getElementById("bg").style.backgroundImage = "url(https://image.ibb.co/nOtP2U/2.png)";
}, false);
document.getElementById("b").addEventListener("mouseout", function() {
    document.getElementById("bg").style.backgroundImage = "";
}, false);

 #bg { 
    width: 100px;
    height: 100px;
    background-image: url(https://www.gravatar.com/avatar/d5d2cf334288dd34914b29fd5d941e56?s=32&d=identicon&r=PG)
}

<a id="a" href="" > A</a>

<br></br>

<a id="b" href="" > B</a>

<br></br>

<a id="c" href="" > C</a>

<div id="bg"></div>

Sample (或在片段中查看)

Answer 1

您的问题出在语法上。快速查看控制台可以显示您在代码中遇到的错误。

getElementByI9858d 不是有效方法，您需要使用 getElementById

查看修改后的代码:

document.getElementById("a").addEventListener("mouseover", function() {
  document.getElementById("bg").style.backgroundImage =
    "url(https://www.gravatar.com/avatar/9385da4a3618cdc385bd49fe3d951b78?s=32&d=identicon&r=PG)";
}, false);
document.getElementById("a").addEventListener("mouseout", function() {
  document.getElementById("bg").style.backgroundImage =
    "";
}, false);



document.getElementById("b").addEventListener("mouseover", function() {
  document.getElementById("bg").style.backgroundImage =
    "url(https://image.ibb.co/nOtP2U/2.png)";
}, false);
document.getElementById("b").addEventListener("mouseout", function() {
  document.getElementById("bg").style.backgroundImage =
    "";
}, false);

#bg {
  width: 100px;
  height: 100px;
  background-image: url(https://www.gravatar.com/avatar/d5d2cf334288dd34914b29fd5d941e56?s=32&d=identicon&r=PG)
}

<a id="a" href=""> A</a>

<br /><br />

<a id="b" href=""> B</a>

<br /><br />

<a id="c" href=""> C</a>

<div id="bg"></div>