You mean, the browser makers... What browser are you using? They will have something, you just need to google it.
If you have Word, try copy/pasting into that then highlight the words you want to change and hit Shift + F3. This will convert everything to lower case. YOu can then copy paste back into the browser.
Another option is to open another browswer window. Then go here: http://www.convertcase.net/ and follow the instructions.