JS Bin

var state = '';

function store(){

  state = '';

  var inputs = document.querySelectorAll('input');

  var all = inputs.length;

  while (all--) {

    state += inputs[all].checked ? '1' : '0';

  }

  state = parseInt(state,2);

  output.innerHTML = state;

  buttons[1].disabled = false;

}

function restore(){

  var states = state.toString(2).split('').reverse();

  var inputs = document.querySelectorAll('input');

  var all = inputs.length;

  while (all--) {

    inputs[all].checked = +states[all];

  }

}

var output = document.querySelector('output');

var div = document.querySelector('div');

var out = '';

for(var i=0;i<20;i++) {

  /* out += '<label><input type="checkbox" name="option'+i+'">Option '+i+'</label>';*/

  out += '<input type="checkbox"';

  out += Math.random() > 0.6 ? ' checked' : '';

  out += '>';

}

div.innerHTML = out;

var buttons = document.querySelectorAll('button');

buttons[0].addEventListener('click', function(ev){

  ev.preventDefault();

  store();

});

buttons[1].disabled = true;

buttons[1].addEventListener('click', function(ev){

  ev.preventDefault();

  restore();

});