13. An apparatus comprising at least one processor and at least one memory including computer program code, the at least one memory and the computer program code configured to, with the at least one processor, direct the apparatus at least to: receive, via an active address field, a character string comprising one or more characters, cause repeated checking of validity by repeatedly requesting information on the validity of said character string as a document identifier wherein the checking is implemented by the active address field receiving the character string, cause indication of a valid part of said character string comprising at least a domain part, cause indication of the validity of said character string as a whole by changing an appearance of a control element, wherein the control element is configured to cause a request for a document relating to the document identifier defined by said character string to be sent in response to selection of the control element by a user and wherein the control element does not include an indication of the document identifier defined by said character string; and cause an offering of a possibility to send a request for a document relating to the document identifier defined at least by the valid part of the character string and ignore any other part of said character string.
13. An apparatus comprising at least one processor and at least one memory including computer program code, the at least one memory and the computer program code configured to, with the at least one processor, direct the apparatus at least to: receive, via an active address field, a character string comprising one or more characters, cause repeated checking of validity by repeatedly requesting information on the validity of said character string as a document identifier wherein the checking is implemented by the active address field receiving the character string, cause indication of a valid part of said character string comprising at least a domain part, cause indication of the validity of said character string as a whole by changing an appearance of a control element, wherein the control element is configured to cause a request for a document relating to the document identifier defined by said character string to be sent in response to selection of the control element by a user and wherein the control element does not include an indication of the document identifier defined by said character string; and cause an offering of a possibility to send a request for a document relating to the document identifier defined at least by the valid part of the character string and ignore any other part of said character string. 18. The apparatus according to claim 13 , wherein the document identifier is a web address.