html运行实例（jsck_style_bordertop

代码示例：（标识：jsck_style_bordertop_1）

<!DOCTYPE html>
<html>
<body>

<div id="myDiv">这是 div 元素。</div>
<br>
<button type="button" onclick="myFunction()">设置上边框</button>

<script>
function myFunction() {
  document.getElementById("myDiv").style.borderTop = "thick solid #0000FF";
}
</script>

</body>
</html>