Using the way you’ve described … in Firefox the URL (javascript:window…) that you are linking to has to run in the current window first before it opens in a new window / tab which is why it begins with about:blank (in my testing experience in Firefox this technique leads to the correct URL being displayed so I’m not sure what’s happening with your document)
That being said I find the best way is to run a javascript function on mouse click that has the same call in it. But this way you avoid the “about:blank…” situation.
So, to clarify:
• On mouse click run a new function (call it whatever you want)
• in the function write:
window.open(clickTag, "_blank"); /// _blank is optional
• Then test (don’t forget to include the Head HTML clickTag variable as you have above)
Note window.clickTag is not necessary as this is for setting a variable available globally