브라우저 체크

1. 브라우저 헤더정보
<script language="javascript">
 
function userAgent()
{
    var browserType = "";
    if(navigator.userAgent.indexOf("Chrome") != -1)
    {
        browserType = "CR";
        return browserType;
    }
    if(navigator.userAgent.indexOf("like Gecko") != -1 || navigator.userAgent.indexOf("MSIE") != -1)    //like Gecko는 IE11용
    {
        browserType = "IE";
        return browserType;
    }
    if(navigator.userAgent.indexOf("Firefox") != -1)
    {
        browserType = "FF";
        return browserType;
    }
    if(navigator.userAgent.indexOf("Mozilla") != -1)
    {
        browserType = "MZ";
        return browserType;
    }
    if(navigator.userAgent.indexOf("Opera") != -1)
    {
        browserType = "OP";
        return browserType;
    }
    if(navigator.userAgent.indexOf("Safari") != -1)
    {
        browserType = "SF";
        return browserType;
    }
    if(navigator.userAgent.indexOf("Mac") != -1)
    {
        browserType = "MC";
        return browserType;
    }
}
</script>
2. 객체존재여부
<script language="javascript">
function userAgent()
{
 if(window.ActiveXobject){
  browser = "IE";
  return browserType;
 }
 else {
  browser = "NG";
  return browserType;
 }
}
</script>
[출처] JAVASCRIPT 브라우저 종류 확인|작성자 스위스여행