/* Clearfix for the .slides element */
.slides:after {content: "\0020"; display: block; clear: both; visibility: hidden; line-height: 0; height: 0;}
html[xmlns] .slides {display: block;}
* html .slides {height: 1%;}
/* No JavaScript Fallback */
/* If you are not using another script, such as Modernizr, make sure you
* include js that eliminates this class on page load */
.no-js .slides > li:first-child {display: block;}
<!-- SLIDER HTML -->
<div id="flex-isfb">
<!-- Preloader -->
<div id="preloader"></div>
<style>
/* Preloader */
#preloader {
position: absolute;
top:0;
left:0;
right:0;
bottom:0;
background-color:#fff; /* change if the mask should have another color then white */
z-index:999999999999; /* makes sure it stays on top */
}