addEventListener ( 'message', receiver, false ) Īn event listener is set up to receive messages from document A. The JavaScript for document A will look as follows:įunction receiver ( event ) window. Example Ĭonsider we want document A loaded from to communicate with document B loaded from into an iframe or popup window. PostMessage is not a blocking call messages are processed asynchronously. source - the WindowProxy of where the document came from (the source window).It does not include the path or fragment identifier. This typically includes the scheme, hostname and port.

origin - The origin of the sender document.data - The data, or actual content, of the incoming message.The message event being received has the following attributes: the window which opened the sender document.the parent window of the sender document.windows the sender document explicitly opens through JavaScript calls.other frames or iframes within the sender document's window.As a result, messages can be posted to the following: This requires that the author first obtain the Window object of the receiving document. Using the Messaging API's postMessage method, plain text messages can be sent from one domain to another, e.g. Cross-document messaging allows scripts to interact across these boundaries, while providing a rudimentary level of security.

This practice barred communication between non-hostile pages as well, making document interaction of any kind difficult. Prior to HTML5, web browsers disallowed cross-site scripting, to protect against security attacks. Web Messaging or cross-document messaging, is an API introduced in the WHATWG HTML5 draft specification, allowing documents to communicate with one another across different origins, or source domains while rendered in a web browser.

Messaging for web