13. A computer system comprising: one or more computer processors; an interface to receive, from client computing devices, requests for first electronic documents that are hosted on separate computer systems that are distinct from the computer system; a request processor programmed to obtain, from the separate computer systems, the first electronic documents; a parser programmed to: (i) determine whether or not to process each first electronic document based on an identity of the separate computer system upon which it is hosted, and (ii) when the parser determines to process the first electronic document, identify one or more portions of particular first documents of the first electronic documents that certain of the client computing devices are not configured to interpret or execute, the one or more portions comprising interpreted language elements; an interpreter programmed to convert, in response to the identification by the parser, the one or more portions of the particular documents into one or more portions of replacement content that is of one or more content types that the certain client computing devices are configured to interpret or execute; a document generator programmed to generate, particular second electronic documents that include i) the one or more portions of replacement content and ii) other portions from the particular first documents that the client computing device is configured to interpret or execute; and a response formatter programmed to provide: (i) the first electronic documents to the client computing devices as responses to the requests from the client computing devices when the parser determines to not process the first electronic document, or (ii) the particular second electronic document to the client computing devices as responses to the requests from the client computing devices when the parser determines to process the first electronic document.
13. A computer system comprising: one or more computer processors; an interface to receive, from client computing devices, requests for first electronic documents that are hosted on separate computer systems that are distinct from the computer system; a request processor programmed to obtain, from the separate computer systems, the first electronic documents; a parser programmed to: (i) determine whether or not to process each first electronic document based on an identity of the separate computer system upon which it is hosted, and (ii) when the parser determines to process the first electronic document, identify one or more portions of particular first documents of the first electronic documents that certain of the client computing devices are not configured to interpret or execute, the one or more portions comprising interpreted language elements; an interpreter programmed to convert, in response to the identification by the parser, the one or more portions of the particular documents into one or more portions of replacement content that is of one or more content types that the certain client computing devices are configured to interpret or execute; a document generator programmed to generate, particular second electronic documents that include i) the one or more portions of replacement content and ii) other portions from the particular first documents that the client computing device is configured to interpret or execute; and a response formatter programmed to provide: (i) the first electronic documents to the client computing devices as responses to the requests from the client computing devices when the parser determines to not process the first electronic document, or (ii) the particular second electronic document to the client computing devices as responses to the requests from the client computing devices when the parser determines to process the first electronic document. 15. The computer system of claim 13 , wherein: the interface is further configured to receive, from the client computing devices, information that indicates that users of the client computing devices has selected the selectable link; the interpreter is further configured to execute or interpret, in response to receiving the information, the code that is stored by the storage system, wherein the execution or interpretation of the code causes the dynamic content to be generated; and the response formatter is further configured to provide at least a portion of the dynamic content to the client computing devices.