There are many sites that will validate html. You might wish to point him at some of them to clean up the many errors.
1. the page looks fine in IE 6 & 7, FF 2 & 3, Opera, Safari and now even Chrome, on at least 10-15 different computers I've checked
2. from several millions page views wow-heroes receives each month only few people complain (for example, 550.000+ characters were added to the database since last update - only 8 days ago
....then I don't see the need to fix anything, at least not as a priority.
I did not spend much time looking at it, been busy and stuff like his livequery script are a total mess - I'm not going to take time to reformat it to dig through it
Each person has it's own style in programming, someone's mess is another ones home. And tbh, this "mess" works pretty fine imo, and much faster then someone would expect. Livequery is not my script ofc, I'm really surprised your pro friend is mentioning this one, because it's one of the most popular plugins for JQuery (library used by Google, Dell, Bank of America, NBC, CBS, Mozilla...). Calling it a mess is just....
.... I only use it at one point, and at that point it's done "by the book", just like tutorial on the creators website suggests. Overall, you can just ignore it, since it's only used to make table sort in guild tab less painful.
But it kinda looks like he's trying to be overly clever in how he is embedding data within the page. Things would work much better if he simply emitted the entire page within his php script rather than what he is doing now with the embed.
Things would NOT work much better that way because then the whole page would have to be reloaded, without any need. Also, you would not be able to just switch from Character/Compare/Guild view, or, you would, but the previous page would be destroyed.
If this isn't enough to point him in the right direction, bug me next week and I'll try to take a closer look at it.
Looking forward to hear more suggestions from the expert
At this moment, this website is just my hobby, something on which I try to spend my free time because I like the idea that some people find it helpful. I don't get payed for it, I have a full-time job, and I can't sacrifice any more of those precious spare moments to fix problems which only occur in 0.001% browsers. No offense to your friend, but he sounds like he could make something much better then wow-heroes, which would be great, then I could go back to raiding full time and live a happy life lol
In the meantime, I suggest you try to go to any internet caffe, I'm sure you won't have any problems with wow-heroes from there