1. A method comprising: storing a first version of a particular document in storage accessible to a server-side machine; generating, by the server-side machine, an accessibility-enabled version of the particular document based on the first version of the particular document; wherein the accessibility-enabled version of the particular document has one or more accessibility features, which are not present in the first version of the particular document, that facilitate use of a particular assistive technology; storing the accessibility-enabled version in the storage accessible to the server-side machine; receiving a request, from a client-side machine, for the particular document; determining, by the server-side machine, whether to respond to the request with the first version of the particular document or the accessibility-enabled version of the particular document; responsive to determining to respond to the request with the first version of the particular document, the server-side machine sending the first version of the particular document to the client-side machine; and responsive to determining to respond to the request with the accessibility-enabled version of the particular document, the server-side machine sending the accessibility enabled version of the particular document to the client-side machine.
14. The method of claim 1 , wherein: the particular document is a web page; and the one or more accessibility features comprise one or more of: one or more tags, included in the accessibility-enabled version of the particular document and not included in the first version of the particular document, that facilitate use of the particular assistive technology with the particular document, or one or more tags, not included in the accessibility-enabled version of the particular document and included in the first version of the particular document, that should not be presented to a user by the particular assistive technology for the particular document.