[HTML] pobierz, plaintext 
<textarea id="text"></textarea>
[HTML] pobierz, plaintext 

var text = document.getElementById('text');
var counter= 1;
var counter2 = 0;

    function append_character(){
         console.log(counter);
        if(counter==3) {
         counter = 0;
         }else{
             null;
        }
      counter2++;
      if(counter2==1){
          null;
      }else{
             if(counter==1){
                text.value =  text.value+'-';
        
             }else{
                text.value =  text.value;
             }
      }
      delete counter2;
        counter +=1;
        
    }


text.addEventListener('keypress',append_character,false);