Untitled

<html>
<head>
<script text/javascript>
var inputs = document.getElementsByTagName("input");
function checkTabPress(e)
{

  for(var i=0;i<inputs.length;i++)
 {
   if((inputs[i].value === undefined || inputs[i].value.length == 0) && (e.keyCode == 9))
    {
      alert("plz write");
      return false;

    }


 }
    return true;
}

document.addEventListener('keyup', function (e) {
    checkTabPress(e);
}, false);
</script>
</head>
<body>
Enter Your Name: <input onkeypress="checkTabPress('abc')" type='text' id="abc" placeholder=''><br>
Enter <input onkeypress="checkTabPress('xyz')" type='text' id="xyz" placeholder=''>
</body>
</html>