JSFiddle - React, Tailwind, and code Playground

HTML

<body onload="loadMe();">

    <iframe  name = "myframe" id = "myiframe"> 
    </iframe>  
    
    <script>
    
    function loadMe() {    
        var myform2 = document.createElement("form");
        var input2 = document.createElement("input");
        input2.name = "quantity";
        input2.value = "10";
    
        myform2.appendChild(input2);
    
        var getFrame = document.getElementById('myiframe');
        var doc = getFrame.contentDocument || getFrame.contentWindow.document;
        doc.body.appendChild(myform2); // Does not work.
    }    
    </script>  
    
    
</body>