<style>
* { 
    -webkit-user-modify: read-write;
}
</style>
<script>
    function main() {
        if (window.testRunner)
            testRunner.dumpAsText();
        console.log('The test PASS if it does not crash.')
        document.designMode = "on";
        document.execCommand("selectAll", false, null);
        document.execCommand("italic", false, null);
        document.execCommand("italic", false, null);
    }
</script>

<body onload="main()">
<ruby>
<h1></h1>
<rt>
<p></p>
<input>
</rt>
Hello! This rendering should not crash.
<rp></rp>
</ruby>
