var is_ie = (navigator.userAgent.indexOf('MSIE') >= 0) ? 1 : 0; 
var is_ie5 = (navigator.appVersion.indexOf("MSIE 5.5")!=-1) ? 1 : 0; 
var is_ie8 = (navigator.userAgent.indexOf("MSIE 8.0") >= 0) ? 1 : 0;
var is_opera = ((navigator.userAgent.indexOf("Opera")!=-1)||(navigator.userAgent.indexOf("Opera/6")!=-1)) ? 1 : 0; 
//netscape, safari, mozilla behave the same??? 
var is_netscape = (navigator.userAgent.indexOf('Netscape') >= 0) ? 1 : 0;
var is_mozilla =  (navigator.userAgent.indexOf('Firefox') >= 0) ? 1 : 0;
var is_Safari = (navigator.userAgent.indexOf('Safari') >= 0) ? 1 : 0;


if(is_ie)
{
    if(!is_ie8)
    {
        loadjscssfile('JS/main.JS', 'js');
        loadjscssfile('CSS/main.CSS', 'css');
    }
}

if(is_ie8)
{
    loadjscssfile('JS/main.JS', 'js');
    loadjscssfile('CSS/safari.CSS', 'css');
}

if(is_Safari)
{
    loadjscssfile('JS/main.JS', 'js');
    loadjscssfile('CSS/safari.CSS', 'css');
}

if(is_mozilla)
{
    loadjscssfile('JS/main.JS', 'js');
    loadjscssfile('CSS/safari.CSS', 'css');
}

if(is_opera)
{
     loadjscssfile('JS/main.JS', 'js');
     loadjscssfile('CSS/safari.CSS', 'css');
}

function loadjscssfile(filename, filetype)
{
 if (filetype=="js"){ //if filename is a external JavaScript file
  var fileref=document.createElement('script')
  fileref.setAttribute("type","text/javascript")
  fileref.setAttribute("src", filename)
 }
 else if (filetype=="css"){ //if filename is an external CSS file
  var fileref=document.createElement("link")
  fileref.setAttribute("rel", "stylesheet")
  fileref.setAttribute("type", "text/css")
  fileref.setAttribute("href", filename)
 }
 if (typeof fileref!="undefined")
  document.getElementsByTagName("head")[0].appendChild(fileref)
}