<script>
    var browser=navigator.appName;
    var b_version=navigator.appVersion;
    var version=b_version.split(";");
    var trim_Version=version[1].replace(/[ ]/g,"");
    if(browser=="Microsoft Internet Explorer"
       && trim_Version=="MSIE7.0"){
        alert("IE 7.0");
    }else if(browser=="Microsoft Internet Explorer"
              && trim_Version=="MSIE6.0"){
        alert("IE 6.0");
    }
</script>