介绍：把鼠标放在选择框上实现文字浮现
<!DOCTYPE html>
<html lang="en">
<head><meta charset="UTF-8"><title>第一个JS</title><style>#div1 {width: 100px;height: 100px;background-color: red;border: 1px solid gold;display: none;}</style><script>function f() {document.getElementById('div1').style.display = 'block'}function f1() {document.getElementById('div1').style.display = 'none'}</script>
</head>
<body>
<input type="checkbox" id="in1" onmouseover=f() onmouseout=f1() />
<div id="div1">这是一个JS代码
</div>
</body>
</html>效果图：
