<!DOCTYPE html>
<style>
sub {
    -webkit-user-select: all;
}
.div {
     overflow: scroll;
}
</style>
<script>
onload = () => {
    if (window.testRunner)
        window.testRunner.dumpAsText();
    let div = document.createElement('div');
    div.className = 'div';
    document.body.appendChild(div);
    let span0 = document.createElement('span');
    document.body.appendChild(span0);
    span0.appendChild(document.createElement('div'));
    let span1 = document.createElement('span');
    span0.appendChild(span1);
    div = document.createElement('div');
    div.className = 'div';
    span1.appendChild(div);
    div = document.createElement('div');
    div.className = 'div';
    document.body.appendChild(div);
    document.designMode = 'on';
    document.execCommand('SelectAll');
    document.execCommand('Subscript');
    document.execCommand('Copy');
    document.execCommand('Paste');
    document.write("Test passes if it does not crash.");
};
</script>