How to make a field type inside another? Javascript

Question

I’ve been trying to make whatever I type appear inside another input, but I couldn’t. The point is I got this code here, it runs and it works right, but in my real code it doesn’t run.

window.oninput = function(event){
   
   var campo = event.target.id; // pega o id do campo que chamou o evento
   
   if(campo == "a"){
      document.querySelector('#a-1').value = document.querySelector('#a').value;
   }else if(campo == "a-1"){
      document.querySelector('#a').value = document.querySelector('#a-1').value;
   }
};

<h2>Este campo é diretamente automático</h2>
<input type="text" id="a"> oninput: <input type="text" id="a-1"><br><br>

Answer 1

Use the onkeyup event I believe will help you.

try like this

<input type="text" id="a" onkeyup="document.getElementById('a-1').value = this.value;"> oninput: <input type="text" id="a-1" onkeyup="document.getElementById('a').value = this.value;">

I hope I’ve helped.