1. A method performed by a virtual machine executing on a client computing device for abstracting communications with a data source located remotely from the client computing device, the method comprising: based on an expression in an application that requests a model document using a Uniform Resource Locator (“URL”), identifying, from a first portion of the URL, a communication channel that is configured to access a resource from the data source; instantiating an instance of the identified communication channel configured to communicate with the data source; causing the communication channel to translate a request represented in a second portion of the URL into a format expected by the data source; transmitting the request to the data source; translating content in a response received from the data source into a format of the model document requested by the application; binding a user interface component associated with the application to the model document, wherein the binding associates the user interface component with a URL object that references the model document, and wherein the URL object is provided by the virtual machine; and receiving, by the URL object, a call from the user interface component to cause a data update associated with an event to be implemented on the model document; wherein program logic of the application is defined separately from the virtual machine.
13. The method as recited in claim 1 , wherein translating content in the response includes converting SQL relational data to an XML-based format.