jquery find input:hidden error in safari

I'm trying to implement a feature where a user can click on a row i.e., <tr>, and it'll go to a specific URL.

Here's my HTML and Jquery code:

                <tbody>

  开发者_StackOverflow中文版                  <tr>
                        <input class="threadid_c" id="threadID" name="threadID" type="hidden" value="MzAwMTYwLDMwMDM3Miw=" />
                        <td>
                            ...
        </tr>
                    <tr>
                        <input class="threadid_c" id="threadID" name="threadID" type="hidden" value="MzAwMzcyLDMwMDM4MCw=" />
                        <td>
            ....

        $('#datatable tr').click(function() {
            var x = $(this).find("input:hidden");
            var url = "/User/Ping/" + x.val();
            location.href = url;
        });

This works fine in Chrome, Firefox, and IE. But in Safari, x.val() returns undefined.

I looked in Safari's JavaScript console, I see this message:

<input> is not allowed inside <tr>. Inserting <input> before the <table> instead.

Not sure if that's related to the problem. Any suggestions?

You can't have a <input> as a direct <tr> child just like it says, just tuck it inside the first <td> instead, like this:

<tr>
   <td>
   <input class="threadid_c" name="threadID" type="hidden" value="MzAwMzcyLDMwMDM4MCw=" />
   ....

Also remove the id attribute since it's repeated...they should be unique in the page.