用JS控制IFRAME的内容页面左右滚动

<iframe name= "iframe1" style= "width:100;height:100 " src="ads/personal-lawyer.htm"> </iframe> <br> <input name= "button1" type= "button" value= "左 " onclick=showLeft()> <input name= "button1" type= "button" value= "右 " onclick=showRight()> <input name= "button1" type= "button" value= "上 " onclick=showTop()> <input name= "button1" type= "button" value= "下 " onclick=showDown()> <script language=javascript> function showLeft(){ if(iframe1.document.body.scrollLeft> 0) iframe1.document.body.scrollLeft=parseInt(iframe1.document.body.scrollLeft)-10; } function showRight(){ if(iframe1.document.body.scrollLeft <iframe1.document.body.scrollWidth) iframe1.document.body.scrollLeft=parseInt(iframe1.document.body.scrollLeft)+parseInt(10); } function showTop(){ if(iframe1.document.body.scrollTop> 0) iframe1.document.body.scrollTop=parseInt(iframe1.document.body.scrollTop)-10; } function showDown(){ if(iframe1.document.body.scrollTop <iframe1.document.body.scrollWidth) iframe1.document.body.scrollTop=parseInt(iframe1.document.body.scrollTop)+parseInt(10); } </script>
[提示：你可先修改部分代码，再按运行]