I suggest using this code:

var containerAll = document.querySelectorAll("div.editablediv");
for(var i=0; i<contenidoaguardar.length;i++){
containerAll[i].innerHTML = contenidoaguardar[i][0];
savetextbox(i)
}

The correction made in this code is that the < operator is used instead of <= in the for loop condition. This fixes the error, and now the code will process all elements in the contenidoaguardar array.