Regular expression for URL validation

/^(?:https?|s?ftp|telnet|ssh|scp):\/\/(?:(?:[\w]+:)?\w+@)?(?:(?:(?:[\w-]+\.)*\w[\w-]{0,66}\.(?:[a-z]{2,6})(?:\.[a-z]{2})?)|(?:(?:25[0-5]\.|2[0-4][0-9]\.|1[0-9]{2}\.|[0-9]{1,2}\.)(?:(?:25[0-5]|2[0-4][0-9]|1[0-9]{2}|[0-9]{1,2})\.){2}(?:25[0-5]|2[0-4][0-9]|1[0-9]{2}|[0-9]{1,2})))(?:\:\d{1,5})?(?:\/(~[\w-_.])?)?(?:(?:\/[\w-_.]*)*)?\??(?:(?:[\w-_.]+\=[\w-_.]+&?)*)?$/i;

This will do the job.