15. A method for communicating between iframes, comprising: instantiating two or more iframes within a browser application running on a computing device; loading scripts containing structured control flow of a scripting language into two or more of the iframes; generating one or more type-checked interfaces in each iframe from one or more pre-defined proxy stubs for use in processing any serialized text message received from any other iframe; transforming at least a portion of the scripts loaded into one or more of the iframes to cause the transformed scripts within those iframes to generate one or more annotated serialized text messages representing corresponding structured control flow when the transformed scripts initiate corresponding actions within those iframes; transmitting each annotated serialized text message from its corresponding iframe to one or more of the other iframes via a browser postMessage channel; and within any iframe receiving any annotated serialized text message from any other iframe, deserializing that message and converting it back into the corresponding structured control flow for execution within the receiving iframe.
15. A method for communicating between iframes, comprising: instantiating two or more iframes within a browser application running on a computing device; loading scripts containing structured control flow of a scripting language into two or more of the iframes; generating one or more type-checked interfaces in each iframe from one or more pre-defined proxy stubs for use in processing any serialized text message received from any other iframe; transforming at least a portion of the scripts loaded into one or more of the iframes to cause the transformed scripts within those iframes to generate one or more annotated serialized text messages representing corresponding structured control flow when the transformed scripts initiate corresponding actions within those iframes; transmitting each annotated serialized text message from its corresponding iframe to one or more of the other iframes via a browser postMessage channel; and within any iframe receiving any annotated serialized text message from any other iframe, deserializing that message and converting it back into the corresponding structured control flow for execution within the receiving iframe. 20. The method of claim 15 wherein the control flow includes one or more of statically typed checked method calls, event calls, progress indicators and asynchronous tasks.