[javascript] In jQuery, how do I get the value of a radio button when they all have the same name?

Here is my code:

<table>
   <tr>
      <td>Sales Promotion</td>
      <td><input type="radio" name="q12_3" value="1">1</td>
      <td><input type="radio" name="q12_3" value="2">2</td>
      <td><input type="radio" name="q12_3" value="3">3</td>
      <td><input type="radio" name="q12_3" value="4">4</td>
      <td><input type="radio" name="q12_3" value="5">5</td>
   </tr>
</table>
<button id="submit">submit</button>

Here is JS:

$(function(){
    $("#submit").click(function(){      
        alert($('input[name=q12_3]').val());
    });
 });

Here is JSFIDDLE! Every time I click button it returns 1. Why? Can anyone help me?

$('input:radio[name=q12_3]:checked').val();

There is another way also. Try below code

$(document).ready(function(){

      $("input[name='gender']").on("click", function() {
            alert($(this).val());
        });
});

You might want to change selector:

$('input[name=q12_3]:checked').val()

in your selector, you should also specify that you want the checked radiobutton:

$(function(){
    $("#submit").click(function(){      
        alert($('input[name=q12_3]:checked').val());
    });
 });

use this script

$('input[name=q12_3]').is(":checked");

DEMO : https://jsfiddle.net/ipsjolly/xygr065w/

$(function(){
    $("#submit").click(function(){      
        alert($('input:radio:checked').val());
    });
 });