一个关于HTML的问题

Question

<SCRIPT LANGUAGE="JavaScript">
<!--
function radio(bool)
{
document.form1.t1.readOnly = bool;
}
//-->
</SCRIPT>
<form method="post" action="some.jsp" name="form1">
<table>
<tr><td>
<input type="radio" name="perid" value="1" onclick="radio(true)">是
<input type="radio" name="perid" value="0" checked onclick="radio(false)">否
</td></tr>
<tr>
<td><input type="text" name="t1"></td>
</tr>
</form>
<table>

Answer 1

<form method="post" action="some.jsp" name="form1">
<table>
<tr><td>
<input type="radio" name="perid" value="1" onclick=this.form.t1.readOnly=1>是
<input type="radio" name="perid" value="0" checked onclick=this.form.t1.readOnly=0>否
</td></tr>
<tr>
<td><input type="text" name="t1"></td>
</tr>
</form>
<table>

Answer 2

<form method="post" action="some.jsp" name="form1">
<table>
<tr><td>
<input type="radio" name="perid" value="1" onclick="form1.t1.readOnly=false">是
<input type="radio" name="perid" value="0" onclick="form1.t1.readOnly=true" checked>否
</td></tr>
<tr>
<td><input type="text" name="t1" readOnly></td>
</tr>
</form>
<table>