<!DOCTYPE html>
<html>
<head>
    <meta name="viewport" content="width=device-width, initial-scale=1">
    <script>
        addEventListener("DOMContentLoaded", () => {
            let target = document.getElementById("target");
            getSelection().setPosition(target, 1);
        });
    </script>
</head>
<body contenteditable>
Hello world.
<br id="br1">
<div style="background: tomato;" id='target'>F</div>
<br id="br2">
This is a test.
</body>
</html>