Some javascript code that allows you to automatically delete all members from a facebook group.

fb_delete_allgroupmembers.js

// first go to https://www.facebook.com/groups/XXXX/members/
// then paste this in the javascript console
deleteAll = [];
deleteAll.elms = [];
 
deleteAll.canClick = function (el) {
  return (typeof el != 'undefined') && (typeof el.click != 'undefined');
}
 
deleteAll.load = function() {
  deleteAll.elms = document.getElementsByClassName("uiPopoverButton _p uiButton uiButtonSuppressed uiButtonNoText");
  if (i < deleteAll.elms.length - 5 && !more[0].hasChildNodes()) {
    setTimeout(deleteAll.getMore, 1000);
  } else {
    setTimeout(deleteAll.go, 2000);
  }
}
 
deleteAll.getMore = function() {
  more = document.getElementsByClassName("pam uiBoxLightblue uiMorePagerPrimary");
  if (typeof more != 'undefined' && deleteAll.canClick(more[0])) { 
    more[0].click();
    setTimeout(deleteAll.load, 2000);
  } else {
    setTimeout(deleteAll.load, 100);
  }
}
 
deleteAll.go = function() {
  try {
    deleteAll.doClick(1);
  } catch(e) {
    setTimeout(deleteAll.load, 1000);
  } finally {
    setTimeout(deleteAll.load, 500000);
  }
}
 
deleteAll.doClick = function(i) {
  deleteAll.elms[i].click();
  setTimeout(function(){deleteAll.doClick2(i)}, 1000);
}

deleteAll.doClick2 = function(i) {
  document.getElementsByClassName("_54nc")[1].click()
  setTimeout(function(){deleteAll.confirm(i)}, 1000);
}
 
deleteAll.confirm = function (i) {
  remove_but = document.getElementsByClassName("_42ft _42fu layerConfirm uiOverlayButton selected _42g- _42gy")[0];
  more = document.getElementsByClassName("pam uiBoxLightblue uiMorePagerPrimary");
  
  if ((i < deleteAll.elms.length - 5 || !more[0].hasChildNodes()) && deleteAll.canClick(remove_but) && remove_but.value == "1") {
    remove_but.click();
    setTimeout(function(){deleteAll.confirm2(i)}, 1000);
  } else {
    setTimeout(deleteAll.getMore, 2000);
  }
}
 
deleteAll.confirm2 = function(i) {
	node = document.getElementsByClassName('uiContextualLayerPositioner uiLayer hidden_elem')[0];
	node.parentNode.removeChild(node);
    setTimeout(function(){deleteAll.doClick(i)}, 1000);
} 
 
deleteAll.load();

it didn't work for me,
"ReferenceError: i is not defined"
what is "i"?

This code works! Facebook disabled the native console brownser, but if you install the "Firebug" extension and run this script, it will work for you!

This script does not delete the group, just all the other members and then terminates execution.

IF YOU WANT NOT TO INSTALL THE FIREBUG EXTENSION, YOU CAN ACTIVATE THE USE OF THE CONSOLE HERE: https://www.facebook.com/selfxss

I created a script that works with the new facebook layout: https://gist.github.com/michaelv/11145168
Enjoy!
Some pieces of the code were copied from this gist.

Babrath, can this script be tailored to dump out the blocked list? I need to clean it out as it's over 9k, and we can't tell if a member is messing with the current membership by deleting them, or blocking them indiscriminately.

how do you run this on Mac Chrome?? Please help I need to delete two groups ASAP