Javascript within weblink

I have a menu with 4 items, 3 are pages 1 is a link to an external site, im using wayfinder, and all works fine, on the 4th one when i click it i need it to open in a new window at a specific size with no scrolling or url bar.

this is how the link looks when its normally in a web page html:



I have it so when i click the link it opens a new window but it opens in a full window.

i tried adding a chunk and putting the full link in there, and then put [[$weblink]] in the weblink url field, but that doesn't work.

any ideas gratefully appreciated.

I would add that fourth item as the last part of Wayfinder's outerTpl. The outerTpl is the one that has the enclosing ul tags, so I'd have it like this:

You are a star, worked perfectly, thank you..