这样试试
<HTML>
<HEAD>
<TITLE> New Document </TITLE>
<script language="Javascript">
function t(){
document.all.b2.onclick = function (){ alert("b2");};
}
</script>
</HEAD>
<BODY>
<input name="b1" type="button" value="ttt" onClick="t()">
<input name="b2" type="button" value="b22222" >
</BODY>
</HTML>
<HTML>
<HEAD>
<TITLE> New Document </TITLE>
<script language="Javascript">
function t(){
document.all.b2.onclick = function (){ alert("b2");};
}
</script>
</HEAD>
<BODY>
<input name="b1" type="button" value="ttt" onClick="t()">
<input name="b2" type="button" value="b22222" >
</BODY>
</HTML>
b2.onclick= function(){alert('b2');}
}
var code = "alert('原来的')"
function test() {
eval(code);
}
</script>
<input type=button value=按钮1 onclick="code='alert(\'新的\')'">
<input type=button value=按钮2 onclick="test()">