Chrome does not render <form> tag, FF does

I have a very annoying issue. My website has a form, which works in Firefox but not in IE or Chrome. It's made with Gravity Forms for WordPress, but that has probably nothing to do with the issue since the same issue occured with another form plugin. It seems that the error is in my site.

It's fairly simple: Chrome and IE do not render the tag. It's just completely missing from the DOM. Firefox is fine, form works and all. I checked in Chrome's debugger, it's just not there!

What could possibly be a reason for that? I checked for things such as typos, nothing there. Can't really show you the website, it's behind a VPN.

Any help is greatly appreciated.

Kind regards,

Reinder

EDIT:

To be clear, the form is rendered on screen, it's just not visible in the DOM. The actual result of this is that the form cannot be submitted, it redirects to the site frontpage without posting any data. The source code is the same, both in Chrome and FF.

<div id="middle">
<h2 class="uitgelicht">Partner aanvraag</h2>
<div id="uitgelicht" class="shadow" style="margin-top: 0">
    <div class="uitgelicht-item">
        <div class='gform_wrapper' id='gform_wrapper_1'>
            <form method='post' enctype='multipart/form-data' id='gform_1' class='' action='http://afastennisclassics.nl/partner-aanvraag/'>
                <div class='gform_heading'>
                    <h3 class='gform_title'>Partner Aanvraag</h3>
                    <span class='gform_description'></span>
                </div>
                <div class='gform_body'>
                    <ul id='gform_fields_1' class='gform_fields top_label'>
                        <li id='field_1_1' class='gfield'>
                            <label class='gfield_label'>
                                Selecteer hieronder waarin u geïnteresseerd bent.<span class='gfield_required'>*</span>
                            </label>
                            <div class='ginput_container'>
                                <ul class='gfield_checkbox' id='input_1_1'>
                                    <li class='gchoice_1_1'>
                                        <input name='input_1.1' type='checkbox' value='Hospitality Ruimte' id='choice_1_1' tabindex='1' />
                                        <label for='choice_1_1'>
                                            Hospitality Ruimte
                                        </label>
                                    </li>
                                    <li class='gchoice_1_2'>
                                        <input name='input_1.2' type='checkbox' value='VIP-loge' id='choice_1_2' tabindex='2' />
                                        <label for='choice_1_2'>
                                            VIP-loge
                                        </label>
                                    </li>
                                    <li class='gchoice_1_3'>
                                        <input name='input_1.3' type='checkbox' value='VIP-business seat passe-partout' id='choice_1_3' tabindex='3' />
                                        <label for='choice_1_3'>
                                            VIP-business seat passe-partout
                                        </label>
                                    </li>
                                    <li class='gchoice_1_4'>
                                        <input name='input_1.4' type='checkbox' value='Promotiestand' id='choice_1_4' tabindex='4' />
                                        <label for='choice_1_4'>
                                            Promotiestand
                                        </label>
                                    </li>
                                    <li class='gchoice_1_5'>
                                        <input name='input_1.5' type='checkbox' value='Advertentie programmaboek' id='choice_1_5' tabindex='5' />
                                        <label for='choice_1_5'>
                                            Advertentie programmaboek
                                        </label>
                                    </li>
                                </ul>
                            </div>
                        </li>
                        <li id='field_1_2' class='gfield'>
                            <label class='gfield_label' for='input_1_2'>
                                Bedrijfsnaam<span class='gfield_required'>*</span>
                            </label>
                            <div class='ginput_container'>
                                <input name='input_2' id='input_1_2' type='text' value='' class='medium' tabindex='6' />
                            </div>
                        </li>
                        <li id='field_1_3' class='gfield'>
                            <label class='gfield_label' for='input_1_3'>
                                Contactpersoon<span class='gfield_required'>*</span>
                            </label>
                            <div class='ginput_container'>
                                <input name='input_3' id='input_1_3' type='text' value='' class='medium' tabindex='7' />
                            </div>
                        </li>
                        <li id='field_1_4' class='gfield'>
                            <label class='gfield_label' for='input_1_4'>
                                Straat<span class='gfield_required'>*</span>
                            </label>
                            <div class='ginput_container'>
                                <input name='input_4' id='input_1_4' type='text' value='' class='medium' tabindex='8' />
                            </div>
                        </li>
                        <li id='field_1_12' class='gfield'>
                            <label class='gfield_label' for='input_1_12'>
                                Huisnummer<span class='gfield_required'>*</span>
                            </label>
                            <div class='ginput_container'>
                                <input name='input_12' id='input_1_12' type='text' value='' class='small' tabindex='9' />
                            </div>
                        </li>
                        <li id='field_1_6' class='gfield'>
                            <label class='gfield_label' for='input_1_6'>
                                Postcode<span class='gfield_required'>*</span>
                            </label>
                            <div class='ginput_container'>
                                <input name='input_6' id='input_1_6' type='text' value='' class='medium' maxlength='6' tabindex='10' />
                            </div>
                        </li>
                        <li id='field_1_7' class='gfield'>
                            <label class='gfield_label' for='input_1_7'>
                                Woonplaats<span class='gfield_required'>*</span>
                            </label>
                            <div class='ginput_container'>
                                <input name='input_7' id='input_1_7' type='text' value='' class='medium' tabindex='11' />
                            </div>
                        </li>
                        <li id='field_1_8' class='gfield'>
                            <label class='gfield_label' for='input_1_8'>
                                Telefoon<span class='gfield_required'>*</span>
                            </label>
                            <div class='ginput_container'>
                                <input name='input_8' id='input_1_8' type='text' value='开发者_如何学运维' class='medium' tabindex='12' />
                            </div>
                        </li>
                        <li id='field_1_9' class='gfield'>
                            <label class='gfield_label' for='input_1_9'>
                                Fax
                            </label>
                            <div class='ginput_container'>
                                <input name='input_9' id='input_1_9' type='text' value='' class='medium' tabindex='13' />
                            </div>
                        </li>
                        <li id='field_1_10' class='gfield'>
                            <label class='gfield_label' for='input_1_10'>
                                E-mail<span class='gfield_required'>*</span>
                            </label>
                            <div class='ginput_container'>
                                <input name='input_10' id='input_1_10' type='text' value='' class='medium' tabindex='14' />
                            </div>
                        </li>
                        <li id='field_1_11' class='gfield'>
                            <label class='gfield_label' for='input_1_11'>
                                Opmerkingen
                            </label>
                            <div class='ginput_container'>
                                <textarea name='input_11' id='input_1_11' class='textarea medium' tabindex='15' rows='10' cols='50'>
                                </textarea>
                            </div>
                        </li>
                    </ul>
                </div>
                <div class='gform_footer top_label'>
                    <input type='submit' id='gform_submit_button_1' class='button gform_button' value='Versturen' tabindex='16' /><input type='hidden' class='gform_hidden' name='is_submit_1' value='1' /><input type='hidden' class='gform_hidden' name='gform_submit' value='1' /><input type='hidden' class='gform_hidden' name='gform_unique_id' value='4d9232a629d23' /><input type='hidden' class='gform_hidden' name='state_1' value='YToyOntpOjA7czo2OiJhOjA6e30iO2k6MTtzOjMyOiIwN2YwYmQxNTkyNWFkN2MwZjBkMjZkZjk3YjYzNjc3YiI7fQ==' /><input type='hidden' class='gform_hidden' name='gform_target_page_number_1' id='gform_target_page_number_1' value='0' /><input type='hidden' class='gform_hidden' name='gform_source_page_number_1' id='gform_source_page_number_1' value='1' /><input type='hidden' name='gform_field_values' value='' />
                </div>
            </form>
        </div><!-- <a href="#" class="leesmeer">Terug</a> //--><span class="social"><a href="http://twitter.com/share" class="twitter-share-button" data-count="horizontal">Tweet</a>
            <script type="text/javascript" src="http://platform.twitter.com/widgets.js">
            </script>
            <iframe src="http://www.facebook.com/plugins/like.php?href=www.afastennisclassics.nl&amp;layout=button_count&amp;show_faces=false&amp;width=100&amp;action=like&amp;font=tahoma&amp;colorscheme=light&amp;height=21" scrolling="no" frameborder="0" style="border:0px; overflow:hidden; width: 110px; height:21px; margin-bottom:-1px;" allowTransparency="true">
            </iframe>
        </span>
    </div>
</div>
<br clear="both" />

Apparently there was another not-closed on the page, the searchbox missed a > . Chrome doesn't like that.