if(navigator.appVersion.indexOf("Mac") != -1)
{
    if(navigator.userAgent.indexOf("Safari") != -1)
    {
        document.write("<link href=\"_css/SiteStyles_mac_safari.css\" rel=\"stylesheet\" type=\"text/css\"></link>");
    }
    else if(navigator.userAgent.indexOf("Firefox") != -1)
    {
        document.write("<link href=\"_css/StyleSheet_ff.css\" rel=\"stylesheet\" type=\"text/css\"></link>");
    }
    else
    {
        document.write("<link href=\"_css/SiteStyles_mac_safari.css\" rel=\"stylesheet\" type=\"text/css\"></link>");
    }
}
else if(navigator.userAgent.indexOf("Firefox") != -1)
{
    document.write("<link href=\"_css/StyleSheet_ff.css\" rel=\"stylesheet\" type=\"text/css\"></link>");
}
else if(navigator.userAgent.toLowerCase().indexOf('chrome') != -1)
{
    document.write("<link href=\"_css/StyleSheet_chrome.css\" rel=\"stylesheet\" type=\"text/css\"></link>");
}
else if(navigator.userAgent.indexOf("Safari") != -1)
{
    document.write("<link href=\"_css/SiteStyles_mac_safari.css\" rel=\"stylesheet\" type=\"text/css\"></link>");
}
else if(navigator.userAgent.indexOf("MSIE 6") != -1)
{
    document.write("<link href=\"_css/StyleSheetIE6.css\" rel=\"stylesheet\" type=\"text/css\"></link>");
}