help for Url detection regex

I hope this question is not a duplicate but I didn't find anything equivalent on SO.

I want a regex for checking an URL.

The given URL can be local /some-text or extern开发者_JAVA技巧al http://theurl

I am trying ^http://|/[-\w/\.]+$ but it doesn't work.

I don't know how to write the optional http://. Any help?

Thanks

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Try:

^(https?://|/)[\w/.-]+$

or, if you care about // at the begining:

^(https?://|/)[^/]+[\w/.-]*$