javascript - 显示/隐藏 div onmouseover/onmouseout Javascript

Question

我的页面上有一个超链接。我想在鼠标悬停在超链接上时显示一个 div，并在鼠标移开时隐藏它。

我的 html:

<a onmouseover="showDiv(this)" onmouseout="hideDiv(this)">
    <img>
    <div class="inner-block">
         Content
    </div>
</a>

Javascript:

function showDiv(elem) {
    elem.getElementsByTagName("div").style.visibility="visible";
}

function hideDiv(elem) {
    elem.getElementsByClassName("inner-block2").style.visibility="hidden";
}

和 CSS:

.inner-block {
    visibility: hidden
}

我已经尝试了 getElementsByTagName、getElementsByClassName，无论我尝试什么我都会得到

Uncaught TypeError: Cannot set property 'visibility' of undefined

Answer 1

试试这个:

function showDiv(elem) {
    elem.getElementsByTagName("div")[0].style.visibility="visible";
}

function hideDiv(elem) {
    elem.getElementsByTagName("div")[0].style.visibility = "hidden"
}

因为 getElementsByClassName("inner-block2") 将返回 NodeList