1. A method for providing alternative text for use in association with image data specified by a URI, said method comprising: processing, by a web browser application program, code for a web page to display the web page; identifying, by the web browser application program, from the code a URI specifying an image data file for an image to be displayed in the web page; determining, by the web browser application program, whether the URI of the image data file includes alternative text for the image encoded using a reserved character in URL syntax, the reserved character being contextually redundant in the context of a source image data file; in response to the URI of the image data file lacking the reserved character, loading the image for display in the web page; and in response to the URI of the image data file having the reserved character, extracting the identified alternative text and loading the alternative text for display in the web page in place of the image.
1. A method for providing alternative text for use in association with image data specified by a URI, said method comprising: processing, by a web browser application program, code for a web page to display the web page; identifying, by the web browser application program, from the code a URI specifying an image data file for an image to be displayed in the web page; determining, by the web browser application program, whether the URI of the image data file includes alternative text for the image encoded using a reserved character in URL syntax, the reserved character being contextually redundant in the context of a source image data file; in response to the URI of the image data file lacking the reserved character, loading the image for display in the web page; and in response to the URI of the image data file having the reserved character, extracting the identified alternative text and loading the alternative text for display in the web page in place of the image. 5. The method according to claim 1 wherein said alternative text data comprises one or more other data types.