<html><head><style>table, th, td { border: 1px solid black;}</style></head><body><h3>如何访问 TH 元素的演示</h3><table> <tr> <th id="myTh">Name</th> </tr> <tr> <td>John</td> </tr></table><p>单击该按钮可更改 TH 元素的文本。</p><button onclick="myFunction()">试一试</button><p id="demo"></p><script>function myFunction() { var x = document.getElementById("myTh"); x.innerHTML = "新的表格标题";}</script></body></html>