Rambomst, bumping isn't liked here. We're a slow moving enough board that if someone has an answer, we answer.
I'll be a bit firmer with my answer. Source HTML is limited. If the ULX default motd displays fine, and you only have trouble when you attempt to add non-static javascript, it is most likely 1) Source html decoder not liking non-static pages, or 2) an error in your javascript.
See my quote from 2007.
ULib uses the html engine provided by Source, the same engine code that every other Source game uses.
<clip>
However, though the Source engine html interpreter is based off of internet explorer, it is limited, for several reasons including security, in what it can do.
<clip>
I've recently tried to use javascript and a <div> tag to dynamically update a page and discovered that Source won't allow dynamicly updating a page once its already been presented.
I believe it also won't allow download of files. (it won't prompt where to save them)
<clip
Updates have been made to Gmod as of late. It wouldn't surprise me if the Source decoder has been changed within Gmod, nothing to do with ULX... all we do is throw the html code at the decoder within Gmod.
I'm not sure if Source relies on Internet Explorer anymore. I'm thinking when the Steam GUI changed, they started using a new web kit (since they're going towards Linux/Mac, no IE on those)
I've seen complaints on Facepunch about other motd mods where people say a motd that worked fine one day doesn't the next.
I'm guessing point 1.