selectAll.click(function(){
          langs.prop('checked',this.checked);
          selectAllLabel.toggle(!this.checked);
          deselectAllLabel.toggle(this.checked);
        });

        invertSelect.click(function(){
          langs.map(function(k,v){
            $(v).prop('checked',!v.checked);
          });
          langs.change();
        });

        langs.change(function(){
          var count = 0;
          langs.map(function(k,v){
            if(v.checked){
              count++;
            }
          });
          selectAll.prop('checked',count===langs.length);
          selectAllLabel.toggle(!(count===langs.length));
          deselectAllLabel.toggle(count===langs.length);
        });