onclick open window and specific size
<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>
Where width and height are pixels without units (width=400 not width=400px).
In most browsers it will not work if it is not written without line breaks, once the variables are setup have everything in one line:
<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>
window.open('http://somelocation.com','mywin','width=500,height=500');
window.open ("http://www.javascript-coder.com",
"mywindow","menubar=1,resizable=1,width=350,height=250");
from
http://www.javascript-coder.com/window-popup/javascript-window-open.phtml
:]