demo.htm<iframe name="in" src="in.htm"></iframe>
<div align="center" style="height:130px;width:243px;">
<script>var timer;</script>
<br>
<input type="button" value="up"
onmousedown="timer1=setInterval('parent.frames[\'in\'].scrollBy(0,-1)',10)"
onmouseup="clearInterval(timer1)">
<input type="button" value="down"
onmousedown="timer1=setInterval('parent.frames[\'in\'].scrollBy(0,1)',10)"
onmouseup="clearInterval(timer1)" >
</div>in.htm<br>0<br>0<br>0<br>0<br>0<br>0<br>0<br>0<br>0<br>0<br>0<br>0<br>0<br>0<br>0<br>0<br>0<br>0<br>0<br>0<br>0<br>0<br>0<br>0<br>0<br>0<br>0<br>0<br>0<br>0<br>0<br>0<br>0<br>0<br>0<br>0<br>0<br>0<br>0<br>0<br>0<br>0<br>0<br>0<br>0<br>0<br>0
<div align="center" style="height:130px;width:243px;">
<script>var timer;</script>
<br>
<input type="button" value="up"
onmousedown="timer1=setInterval('parent.frames[\'in\'].scrollBy(0,-1)',10)"
onmouseup="clearInterval(timer1)">
<input type="button" value="down"
onmousedown="timer1=setInterval('parent.frames[\'in\'].scrollBy(0,1)',10)"
onmouseup="clearInterval(timer1)" >
</div>in.htm<br>0<br>0<br>0<br>0<br>0<br>0<br>0<br>0<br>0<br>0<br>0<br>0<br>0<br>0<br>0<br>0<br>0<br>0<br>0<br>0<br>0<br>0<br>0<br>0<br>0<br>0<br>0<br>0<br>0<br>0<br>0<br>0<br>0<br>0<br>0<br>0<br>0<br>0<br>0<br>0<br>0<br>0<br>0<br>0<br>0<br>0<br>0
http://home.xmu.edu.cn/~hicazm/design/exercise/skills/sk9.htm