<!DOCTYPE html>
<html>
<style>
#destination {
background-color: green;
/* this is needed to simulate pasting forced colors into a non-forced colors element */
forced-color-adjust: none;
}
</style>
<div>
<div id="target">Copy this line</div>
<div id="other">and this line</div>
</div>
Paste here:
<div id="destination" contenteditable>Copy this line
<br>
and this line
</div>
<script>
// Remove focus to remove caret from test result image
document.getElementById('destination').blur();
</script>
</body>
</html>