試一試 - CSS text-overflow

<!DOCTYPE html>
<html>
<head>
<style>
div.test {
   white-space: nowrap;
   width: 200px;
   overflow: hidden;
   border: 1px solid #000000;
}

div.test:hover {
   text-overflow: inherit;
   overflow: visible;
}
</style>
</head>
<body>

<p>Hover over the two divs below, to see the entire text.</p>
<div class="test" style="text-overflow:ellipsis;">This is some long text that will not fit in the box</div>
<br>
<div class="test" style="text-overflow:clip;">This is some long text that will not fit in the box</div>

</body>
</html>