Thanks, that´s a good idea, but I forget to say that the URL is an argument entered by the user, then i need to prevent any character in the URL.
In this case I´ll need the entire table character-code of the 'aplication/x-www-form-encoded' code.
If anybody can give me a way to find this codes, I´ll have the complete solution. (I was trying to find it int the net with no results)