Get the data-id of the selected option in a datalist

Question

Ok, I have the following HTML source:

<form method="post" action="/" id="search">
  <input list="animals" name="animal">
    <datalist id="animals">
      <option label="Alaskan Malamute" data-id="d8c" value="Dog">
      <option label="Siberian Husky" data-id="w30" value="Dog">
      <option label="Aegean" data-id="rxx" value="Cat">
    </datalist>
</form>

And the JS

function doKeyUp(e) {
  if (e.preventDefault) e.preventDefault();

  if(e.keyCode == 37 || e.keyCode == 38 || e.keyCode == 39 || e.keyCode == 40 ) {return;}

  var input = document.getElementById("animal");
  var search_after = input.value.trim();
  var form = document.getElementsByTagName("form")[0];

  var datalist = document.getElementsByTagName('datalist')[0];

  if (search_after.length >= 2) {

    if (e.keyCode == 13 && search_after.length >= 3) {
      var id = "value of data-id";
      // How to obtain and submit the `data-id` of the selected option.
      document.getElementById("search").submit();
    }
  }
}  // dokeyup



document.addEventListener("DOMContentLoaded", function(event) {
  document.getElementById("search").onsubmit = function (e) {
    console.log("SUBMIT");
    return false;
  };

  document.addEventListener( "keyup", doKeyUp, true);
});

When the user then selects an option, how do I get the data-id of the selected <option> - which is the actual data I want to submit and process on the server side.

This is a project where I'm trying to write everything by my self, no jQuery this time.

Know I can do console.log(datalist.options[1]);, but can not figure how I obtain the selected index.

Update March 4: Must ask again, no one who has any tips for me ?

Still not figured this out, and have really run out of ideas... The last I've tried stopped at, before the form submission:

for (var i=0; i<document.getElementById('animals').options.length; i++) {
    if (document.getElementById('animals').options[i].value == document.getElementsByName("animal")[0].value) {
        var id = document.getElementById('animals').options[i].getAttribute('data-id');
        break;
    }
}

Is it in any way possible to get the selected index of the chosen option - or am I still on the wrong path ? This above stops at the first element, anyway.

Answer 1

Check this answer as jquery solution .. & sorry for late reply .

$(function(){
    $('#p').click(function(){
        console.log($("#animals option[value='" + $('#someid').val() + "']").attr('data-id'));
    });
});

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<form method="post" action="/" id="search">
  <input list="animals" name="animal" id="someid">
    <datalist id="animals">
      <option label="Alaskan Malamute" data-id="d8c" value="Dog">
      <option label="Siberian Husky" data-id="w30" value="Dog">
      <option label="Aegean" data-id="rxx" value="Cat">
    </datalist>
    <span id="p">Click</span>
</form>