JSFiddle - React, Tailwind, and code Playground

HTML

<textarea  id="inpt" cols="30" rows="10"></textarea>
<div><input type="submit" value="append" id="btn" style="width:60px;height:20px;background:grey"></div><br>
<iframe id="fr" name="fr" style="width:300px;height:300px;"></iframe>
<script type="text/javascript">
			var _script = document.createElement('script');
			_script.type = 'text/javascript';
			var iFrame =  document.getElementById('fr'),
		    iFrameBody,
		    t = document.getElementById("inpt"),
	        btn = document.getElementById('btn');

		function injectJS(content, val) {
		   if ( iFrame.contentDocument ) 
		   { 
		     iFrameBody = iFrame.contentDocument.getElementsByTagName('body')[0];
		   }
		   else if ( iFrame.contentWindow ) 
		   { 
		     iFrameBody = iFrame.contentWindow.document.getElementsByTagName('body')[0];
		   }
	        iFrameBody.appendChild(content);
        	content.innerHTML = val; 
        	console.log(iFrameBody);    
		}
		
		btn.onclick = injectJS(_script, t.value);
</script>