<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<script language="javascript">
function sel(obj,group){
var list = [];
var groups = 2;//每一组的个数
//定义的时候按最多的算不够的用0填充
var _TheArray = [
[document.getElementById("id1"),document.getElementById("id2")],
[document.getElementById("id3"),0],
[document.getElementById("id4"),document.getElementById("id5")]
]
for (var i=0;i<_TheArray.length;i++)
{
if(_TheArray[i][0] == obj || _TheArray[i][1] == obj )//不对选中项的同组进行操作
{
continue;
}
for(var k = 0; k < groups; k++)
{
_TheArray[i][k].checked = false;
}
}
}
</script>
</head>
<body>第一组: r1<input type="checkbox" name="r1" group="r1" id="id1" onClick="sel(this,'r1')"/>
r2<input type="checkbox" name="r1" group="r1" id="id2" onClick="sel(this,'r1')"><br/>
  第二组: r3<input type="checkbox" name="r2" group="r2" id="id3" onClick="sel(this,'r2')"><br/>
第三组: r4<input type="checkbox" name="r3" group="r3" id="id4" onClick="sel(this,'r3')">
r5<input type="checkbox" name="r3" group="r3" id="id5" onClick="sel(this,'r3')"><br/>
</html>