version=0;
if (navigator.appVersion.indexOf("MSIE")!=-1){
temp=navigator.appVersion.split("MSIE");
version=parseFloat(temp[1]);
}
if (version<=5.5 && version>0) //NON IE browser will return 0
alert("Warning: you are using an unsupported browser. This site requires at least Internet Explorer 5.5 or a Mozilla based browser.");