<html><head><script type="text/javascript">function lighton(){document.getElementById('myimage').src="/i/eg_bulbon.gif"}function lightoff(){document.getElementById('myimage').src="/i/eg_bulboff.gif"}</script></head><body><img id="myimage" onmousedown="lighton()" onmouseup="lightoff()" src="/i/eg_bulboff.gif" width="100" height="180"><p>请点击灯泡，把它点亮！</p></body></html>