clcik on button and open new popup window code example
Example: javascript popup in small window
<a href="/index2.php?option=com_jumi&fileid=3&Itemid=11"
onclick="window.open(this.href,'targetWindow',
`toolbar=no,
location=no,
status=no,
menubar=no,
scrollbars=yes,
resizable=yes,
width=SomeSize,
height=SomeSize`);
return false;">Popup link</a>