Link Editor - Cannot trigger javascript

I've got a problem with the recent update to the link editor.

I used to have three links in my navigation bar to trigger JavaScripts which connected to LocalizeJS to switch the language on my website. The link was a simple/common script like this:

javascript:Localize.setLanguage('en')

Before the update to the link editor, I was able to add a link like the one above. But recently, one of the button is not working so I decided to remove it and recreate a new link but when I try to add the javascript bit to the link editor now, it pop up an error message saying

"Links must be formatted as www.example.com or example.com"

which I've not seen this before the update.

Is there anyway that I can add a javascript to the link editor again or any other ways for me to trigger the function?

Thanks in advance!