How can I filter words in SQL using a function?

How can I filter words in SQL using a function?

I'm having a hard time if I explain it, so I'm giving an example:

What I want is to get the name of the website. I want to select the record with an output like this. How can I remove the 'www.' and '.com' in the record?

How about this?

CREATE FUNCTION dbo.StripWWWandCom (@input VARCHAR(250))
RETURNS VARCHAR(250)
AS BEGIN
    DECLARE @Work VARCHAR(250)

    SET @Work = @Input

    SET @Work = REPLACE(@Work, 'www.', '')
    SET @Work = REPLACE(@Work, '.com', '')

    RETURN @work
END

and then use:

SELECT ID, dbo.StripWWWandCom (WebsiteName)
FROM dbo.YourTable .....

Of course, this is severely limited in that it will only strip www. at the beginning and .com at the end - nothing else (so it won't work on other host machine names like smtp.yahoo.com and other internet domains such as .org, .edu, .de and etc.)