<script>
function onFont(tid){
for(var i = 1 ; ; i ++ ){
var tfont = document.getElementById("font"+i);
if(tfont){
tfont.color = "black";
} else {
break;
}
}
var tfont = document.getElementById("font"+tid);
if(tfont){
tfont.color="red";
}
}
</script>
<table border="1">
<tr>
<td><a href="javascript:onFont('1');"><font id="font1" color="red">aaa</font></a></td>
<td><a href="javascript:onFont('2');"><font id="font2" color="black">bbb</font></a></td>
<td><a href="javascript:onFont('3');"><font id="font3" color="black">ccc</font></a></td>
<td><a href="javascript:onFont('4');"><font id="font4" color="black">ddd</font></a></td>
<td><a href="javascript:onFont('5');"><font id="font5" color="black">eee</font></a></td>
</tr>
</table>