<form id="myform"   name="myform" action=""  class="full">
   <div>
    <input type="text" class="newEnter"  id="nome" tabindex="0"     name="nome" onkeypress="myFunctionChar(event)">
    </div>
    <div>
    <input type="text" class="newEnter" id="endereço" tabindex="1" name="endereço"   onkeypress="myFunctionChar(event)">
    </div>
    <div>
    <input type="text" class="newEnter" id="cidade" tabindex="2" name="cidade" onkeypress="myFunctionChar(event)">
    </div>
    </form>
<script>
        function myFunctionChar(event) {
         //    var h =  event.charCode || event.keyCode;
            //  if (y == 111 || y == 79) {  // o is 111, O is 79
          //      alert("You pressed the 'O' key!");
//            }else{        
                if (event.key=="Enter"){
                    var x = document.getElementById("myform").querySelectorAll("input");
                    document.getElementById("hum").innerHTML=x.length;
                    var y=x[0].tabIndex;
            </script> 
            