function checkUseragent()
{
    var useragent = navigator.userAgent;
    var showAttention = false;
    if (/Firefox[\/\s](\d+\.\d+)/.test(useragent))
    {
        var ffversion=new Number(RegExp.$1)
        if (ffversion < 2)
            showAttention = true;
    }
    else if (/MSIE (\d+\.\d+);/.test(useragent))
    {
        var ieversion=new Number(RegExp.$1)
        if (ieversion < 8)
            showAttention = true;
    }
    else if (/Opera[\/\s](\d+\.\d+)/.test(useragent))
    {
        var oprversion=new Number(RegExp.$1)
        if (oprversion < 9)
            showAttention = true;
    }

    if (!showAttention)
    {
        $("div#anti_ie").remove();
    }
}