<!DOCTYPE html>
<html>
<head>
<style>
table, th, td { border: 1px solid black;
margin-top: 20px;
}
</style>
</head>
<body>
<p>单击该按钮创建一个 CAPTION 元素。</p>
<button onclick="myFunction()">试一试</button>
<table id="myTable">
<tr>
<th>Month</th>
<th>Savings</th>
</tr>
<tr>
<td>January</td>
<td>$100</td>
</tr>
<tr>
<td>February</td>
<td>$50</td>
</tr>
</table>
<script>
function myFunction() { var x = document.createElement("CAPTION"); var t = document.createTextNode("Monthly savings"); x.appendChild(t);
var table = document.getElementById("myTable") table.insertBefore(x, table.childNodes[0]);
}
</script>
</body>
</html>