iframe内容动态修改问题

Question

<input onclick="gameinfo.location.href='cherry.htm'">
<iframe id=gameinfo src='old.htm' frameborder='0' width='556' height='420'>

Answer 1

<A href="javascript:gameinfo.location.href='game/cherry.htm'">
<iframe id=gameinfo src='game/cf3r.htm' frameborder='0' style="width:556;height:420" onload="style.height=gameinfo.document.body.scrollHeight"></iframe>结果被改的还是整个网页

Answer 2

<A href="#" onclick="javascript:gameinfo.location='game/cherry.htm'">
<iframe id="gameinfo" name="gameinfo" src='game/cf3r.htm' frameborder='0'></iframe>

Answer 3

<A href="javascript:void(0)" onclick="gameinfo.location.href='game/cherry.htm'">change</a>
<iframe id=gameinfo src='game/cf3r.htm' frameborder='0' style="width:556;height:420" onload="style.height=gameinfo.document.body.scrollHeight"></iframe>