<!DOCTYPE html>
<head>
<script>
window.onload = function() {
    var inputEl = document.getElementById('searchbox');
    inputEl.focus();
}
</script>
</head>
<body>
<div class="container" data-mode="browsing">
    <div class="wrapper">
        <input id="searchbox" placeholder="Should be focused">
    </div>
</div>
</body>