7. A system comprising: at least a memory and a processor to implement a web application, the web application configured to perform operations comprising: receiving a call from a third party object that requests a domain context; ascertaining the domain context of the third party object; returning the domain context to the third party object; requiring the third party object to include its associated domain context in subsequent calls that the third party object makes; receiving a subsequent call from the third party object; ascertaining, from the subsequent call, the domain context of the third party object; and making a domain context-based decision based on the ascertained domain context by refusing to allow the subsequent call to execute if the third party object's ascertained domain context does not match a target window domain context or allowing the subsequent call to execute if the third party object's ascertained domain context matches the target window domain context.
7. A system comprising: at least a memory and a processor to implement a web application, the web application configured to perform operations comprising: receiving a call from a third party object that requests a domain context; ascertaining the domain context of the third party object; returning the domain context to the third party object; requiring the third party object to include its associated domain context in subsequent calls that the third party object makes; receiving a subsequent call from the third party object; ascertaining, from the subsequent call, the domain context of the third party object; and making a domain context-based decision based on the ascertained domain context by refusing to allow the subsequent call to execute if the third party object's ascertained domain context does not match a target window domain context or allowing the subsequent call to execute if the third party object's ascertained domain context matches the target window domain context. 10. The one or more computer-readable storage media as recited in claim 7 , wherein the making the domain context-based decision comprises refusing to allow the subsequent call to execute.