var ua = navigator.userAgent.toLowerCase();
var is_major = parseInt(navigator.appVersion);
var is_minor = parseFloat(navigator.appVersion);
var is_ie = ((ua.indexOf("msie") != -1) && (ua.indexOf("opera") == -1));
var is_ie3    = (is_ie && (is_major < 4));
var is_ie4    = (is_ie && (is_major == 4) && (ua.indexOf("msie 4")!=-1) );
var is_ie5    = (is_ie && (is_major == 4) && (ua.indexOf("msie 5.")!=-1) );
var is_ie6up  = (is_ie && !is_ie3 && !is_ie4 && !is_ie5);
if(is_ie6up || !is_ie){
document.write('<script type="text/javascript" src="js/smoothscroll.js"></script>');
}