<title>Example of HTML menu Tag</title>
<script type="text/javascript">
var myImg = document.getElementById("sky");
var curr_width = myImg.clientWidth;
alert("Maximum zoom-in level reached.");
myImg.style.width = (curr_width + 50) +"px";
var myImg = document.getElementById("sky");
var curr_width = myImg.clientWidth;
alert("Maximum zoom-out level reached.");
myImg.style.width = (curr_width - 50) +"px";
<img src="/examples/images/sky.jpg" id="sky" width="250" alt="Cloudy Sky" contextmenu="skymenu">
<menu type="context" id="skymenu">
<menuitem label="Zoom In" icon="/examples/images/zoom-in.png" onclick="zoomin()"></menuitem>
<menuitem label="Zoom Out" icon="/examples/images/zoom-out.png" onclick="zoomout()"></menuitem>
<menuitem label="Reload Image" icon="/examples/images/reload.png" onclick="window.location.reload();"></menuitem>
<p><strong>Note:</strong> Right click on the image and select zoom-in, zoom-out or reload option form the contextmenu to understand how it works. This example works only in Firefox.</p>