JSFiddle - React, Tailwind, and code Playground
by Tsuneo Yoshioka
HTML
<div id="menuOverlay">
<button id="btngameIFrame1" runat="server" type="button" onclick="javascript:document.getElementById('gameIFrame1').style.display = 'block';document.getElementById('gameIFrame2').style.display = 'none';">show editor</button>
<button id="btngameIFrame2" runat="server" type="button" onclick="javascript:document.getElementById('gameIFrame1').style.display = 'none';document.getElementById('gameIFrame2').style.display = 'block';">show menu</button>
</div>
<div>
<iframe id="gameIFrame1" style="width: 99%; height: 99%; display: none; position: absolute;" src="http://jgraph.github.io/mxgraph/javascript/examples/grapheditor/www/index.html"></iframe>
<iframe id="gameIFrame2" style="width: 99%; height: 99%; display: block; position: absolute;" src="http://jgraph.github.io/mxgraph/javascript/"></iframe>
</div>
CSS
body{
margin:0 auto;
background:#F0F0F0;}
#menuOverlay {
position:fixed; /*or absolute*/
top: 20px;
left: 20px;
z-index: 999; /* or greater value */
}