<html>
<head>
<style>
table, th, td {
border: 1px solid black;
}
</style>
</head>
<body>
<h3>A demonstration of how to access a TH element</h3>
<table>
<tr>
<th id="myTh">Name</th>
</tr>
<tr>
<td>John</td>
</tr>
</table>
<p>Click the button to change the text of the TH element.</p>
<button onclick="myFunction()">Try it</button>
<p id="demo"></p>
<script>
function myFunction() {
var x = document.getElementById("myTh");
x.innerHTML = "New Table Header";
}
</script>
</body>
</html>