selectAll.change(function (){
  if(selectAll.is(':checked')){
    langs.prop('checked',true);
    selectAllLabel.hide();
    deselectAllLabel.show();
  }else{
    langs.prop('checked',false);
    selectAllLabel.show();
    deselectAllLabel.hide();
  }
});
langs.change(function (){
  let tmp = true;
  for(let i=0;i<langs.length;i++){
    if(!langs[i].is(':checked') ){
      tmp = false;
    }
  }
  if(tmp){
    selectAll.prop('checked',true);
    selectAllLabel.hide();
    deselectAllLabel.show();
  }else{
    selectAll.prop('checked',false);
    selectAllLabel.show();
    deselectAllLabel.hide();
  }
});
invertSelect.click(function (){
  for(let i=0;i<langs.length;i++){
    //langs[i].prop('checked',!langs[i].is(':checked'));
    langs[i].checked = !langs[i].checked;
  }
  langs.change();
});