text: window.onload = function(){
  
      var quantity = document.getElementById("quantity")
      var error = document.getElementById("errorQuantity")
      var subtotal = document.getElementById('subtotal')
      var total = document.getElementById('total')
      //console.log(quantity.value);
      //console.log(total.value);
      //console.log(quantity.value);
      if (quantity.value === "" || quantity.value === null)
      {
  
          error.innerHTML = "Por favor, seleccione la cantidad deseada"
          error.setAttribute("class","invalid-feedback" )
          quantity.setAttribute("class", "form-control is-invalid")
          quantity.addEventListener("change", change)
          return false;
      }
      //console.log(total.innerText);
      //console.log(subtotal.value);
      //console.log(quantity);
      totalOperacion = parseInt(subtotal.innerHTML) * quantity.value
      total.innerText = totalOperacion;
      console.log(total.innerText);
  
          function change(){
          error.innerHTML = ""
          error.setAttribute("class","" )
          name.setAttribute("class", "form-control")
  
          return
         }
  }
  