How can I make requests to other server(s) (i.e. get a page from any desired server) with a JavaScript within the user\'s browser? There are limitations in place to prevent
This is rather easy... if you know the 'secret' trick almost nobody shares..
It's called Yahoo yql...
So in order to regain 'power to the user' (and returning to the convenient mantra: 'never accept no'), just use http://query.yahooapis.com/ (instead of a php? proxy serverside script).
jQuery would not be strictly needed.
EXAMPLE 1:
Using the SQL-like command:
select * from html
where url="http://stackoverflow.com"
and xpath='//div/h3/a'
The following link will scrape SO for the newest questions (bypassing cross-domain security bull$#!7):
http://query.yahooapis.com/v1/public/yql?q=select%20title%20from%20html%20where%20url%3D%22http%3A%2F%2Fstackoverflow.com%22%20and%0A%20%20%20%20%20%20xpath%3D%27%2F%2Fdiv%2Fh3%2Fa%27%0A%20%20%20%20&format=json&callback=cbfunc
As you can see this will return a JSON array (one can also choose xml) and calling the callback-function: cbfunc.
Indeed, as a 'bonus' you also save a kitten every time you did not need to regex data out of 'tag-soup'.
Do you hear your little mad scientist inside yourself starting to giggle?
Then see this answer for more info (and don't forget it's comments for more examples).
Good Luck!