代码示例:(标识:jsck_state_if_else_2)
<!DOCTYPE html>
<html>
<body>

<img id="myImage" onclick="changeImage()" src="/static/demo/images/eg_bulboff.gif" width="109" height="180">

<p>单击灯泡以打开/关闭灯。</p>

<script>
function changeImage() {
  var image = document.getElementById("myImage");
  if (image.src.match("eg_bulbon")) {
    image.src = "/static/demo/images/eg_bulboff.gif";
  } else {
    image.src = "/static/demo/images/eg_bulbon.gif";
  }
}
</script>

</body>
</html>
运行结果: