实现鼠标滑过按钮时显示文本，滑出时隐藏文本
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>JavaScript</title>
<style>
</style>
</head>
<body>
<p id="text" style="width:100px;border: 1px solid black; visibility: hidden;padding:20px;">HELLO!</p>
<button id="b1" onmouseover="visb()" onmouseout="unvis()">button</button>
<script>
function visb(){
var x=document.getElementById("text")
x.style.visibility='visible';
}
function unvis(){
var x=document.getElementById("text");
x.style.visibility="hidden";
}
</script>
</body>
</html>
