[danik.js]

<style>
    div {
        position: absolute;
        z-index: 100;
        left: 0;
        top: 0;
        right: 0;
        bottom: 0;
        margin: auto;
        width: 100px;
        height: 100px;
 
        border: 1px solid #000;
    }
</style>
<div>ololo</div>