一个快速添加标签的小玩意，但在FF下不能用，望高手指点

初步判断是obj.style.backgroundColor在FF下返回的是rgb(xxx,xxx,xxx)的缘故。偶是新手，代码很菜，高手勿笑啊

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> 
<html xmlns="http://www.w3.org/1999/xhtml"> 
<head> 
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> 
<title>Untitled Document</title> 
<style type="text/css"> 
a.blue:link,a.blue:visited{ 
    font-size: 12px; 
    color: #69c; 
    text-decoration: none; 
} 
a.blue:hover{ 
    background: #69c; 
    color: #fff; 
} 
</style> 
<script type="text/javascript"> 
function fInsert(a,b){ 
    oInput = document.getElementById(a); 
    oItm = b; 
    if(b.style.backgroundColor == "#69c"){     
    sReplace = oItm.innerHTML.concat(" "); 
    oInput.value = oInput.value.replace(sReplace,""); 
    b.style.backgroundColor = ""; 
    b.style.color = ""; 
    } 
    else{ 
    oInput.value = oInput.value.concat(oItm.innerHTML); 
    oInput.value = oInput.value.concat(" "); 
    b.style.backgroundColor = "#69c"; 
    b.style.color = "#fff"; 
    } 
} 
</ script> 
</head> 
<body> 
<input type="text" id="cc" style=" width: 300px;" /> 
关键字　关键字2　关键字3 
</body> 
</html>

[Ctrl+A 全选注:如需引入外部Js需刷新才能执行]

一个快速添加标签的小玩意，但在FF下不能用，望高手指点_表单特效