Bootstrap Dropdown Open On Pageload

Ive got this dropdown styled with bootstrap:

15min

<li class="dropdown open">

That will do the trick.

Solution 2:

This little bit of jQuery script (I'm assuming you've loaded it becasue you're using Bootstrap) ought to do the trick. Once the DOM has loaded, it sends a click() to the dropdown toggle button.

$(document).ready(function () {
    $("#posuvnik").click();
});

There is probably a way to do it in straight CSS, but without seeing more of your code it's hard to know.