url syntax regex

[drew010]

im looking for a regular expression that will tell if a user input url is valid..something simple that will just check for [url]http://[/url] then any number of domains followed by any tld 2-4 characters in length.. ive got something but its not working well.

[ftrudeau]

Tyr this :

(https?://(%[[:digit:]A-Fa-f][[:digit:]A-Fa-f]|[-_.!~*';/?:@&=+$,[:alnum:])+

[drew010]

hey thanks for the code, if i throw an ending delimiter on there for use in preg_match, i get this error next:
Warning: Compilation failed: missing terminating ] for character class at offset 76.
Im not sure where to put that but if i throw it in somewhere then i get the same error except it says its missing terminating ).

thanks again.