I have te necessity to increase the spider_popup_wrap z-index value to 10000000.
<div id="spider_popup_wrap" class="spider_popup_wrap" style="width: 1370px; height: 478px; margin: 0px; top: 0px; z-index: 100000; left: 0px;"> ...
</div>

How can I do this?

Dear Francesco,

Could you please tell us why do you need to implement this?
Thank you.

If you open this link www.losielettronica.it/new/index.php/it/galleria/foto# and you click on one photo, the lightbox will open on fullscreen. The photo will not cover all the page because I have the menu that it has a z-index greater. This is the reason.

Dear Francesco,

Please add the following code to the CSS of your website's template.

#spider_popup_wrap {
    z-index: 2147483647 !important;
}