div don't show up. Why?

Question

I create a javascript + a php page. The script on the php page send data to my sql database, but don't show the result into on my home page.

Here the code

 function getVote(question_ID) { var option_ID = document.querySelector("input[id='option']:checked").value; if (window.XMLHttpRequest) { // code for IE7+, Firefox, Chrome, Opera, Safari xmlhttp = new XMLHttpRequest(); } else { // code for IE6, IE5 xmlhttp = new ActiveXObject("Microsoft.XMLHTTP"); } xmlhttp.onreadystatechange = function() { if (option_ID.readyState == 4 && option_ID.status == 200) { document.getElementById(poll).innerHTML = option_ID.responseText; } } xmlhttp.open("GET", "./core/vote.php?user_ID=" + user_ID + "&question_ID=" + question_ID + "&option_ID=" + option_ID, true); xmlhttp.send(); } 

 <div id="poll"> </div> 

More code

 <div id="poll"> <form method="post" onsubmit='getVote(question_ID);' > <p><?php echo $question ['question_content']; ?></p> <p> <?php $poll_option_selection = "SELECT option_ID, option_content FROM poll_options WHERE question_ID='$question_ID'" ; $poll_option_result = mysqli_query ($connect,$poll_option_selection) ; foreach ($poll_option_result as $poll_option) { $option_ID = $poll_option ['option_ID'] ; $option_content = $poll_option ['option_content'] ; ?> <script type="text/javascript"> var option_ID = <?php echo json_encode($option_ID) ; ?> ; </script> <input type="radio" id="option" value ='<?php echo $option_ID ?>' required /> <?php echo $option_content ?> </br> <?php } ?> <input type="submit"> </form> </div> 

Thank you for your help

Answer 1

It should be:

document.getElementById("poll").innerHTML=option_ID.responseText;

document.getElementById takes the argument (id of element) as a string.