Gets an AuthURL from facebook. The AuthURL must be used to generate a verifier required to obtain the Authentication Token..
|App_Id||String||The app id given to your application by facebook.|
|Callback_Url||String||The url the user will be redirected to after authorizing your application. Note that this must match the Site URL and App Domain you have specified in your facebook app settings.|
|Permissions||String||A comma separated list of permissions to request from the user. Please check the Facebook API for a list of available permissions.|
|URL||String||The url to be entered into a web browser to obtain the verifier token and authorize your facebook app.|