An Introduction to Cross-Document Messaging in Internet Explorer 8

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An Introduction to Cross-Document Messaging in Internet Explorer 8


This article provides an overview of HTML-5.0–compliant cross-document messaging in Internet Explorer 8. The article is intended for Web developers who are interested in exploring the AJAX feature set in more detail.

This topic contains the following sections:

    * The Need for Powerful Custom Pages
    * Browsers Can Make Cross-Frame Messaging Easier and Safer
    * Cross-Document Messaging: A Functional Overview

The Need for Powerful Custom Pages
Generic Web Portals Give Way to Custom Home Pages

Not long ago, Web users would have visited multiple sites to view all of the content that was of interest to them. This isolated content was soon followed by portal sites that were brimming with content, created in an attempt to satisfy the broadest set of user needs. But what about users interested in a more custom "one-stop shop" browsing experience?
Custom Home Pages Need to Communicate Third-Party Components

The need for custom home pages led to the creation of many personalized composite sites. Many of you probably use a few such as Facebook or the Windows Live home page. Such sites allow different modules or "gadgets" to be embedded in the main HTML. For example, consider Abby, a passionate social-networking user who wants to embed a gas-price gadget in her Live.com home page. That page knows her ZIP code, since she typed that in when signing up. She therefore expects that, when she drops the gadget into her home page, the gadget will show locations of the cheapest gas stations in her neighborhood, all without her having to enter the ZIP code again. That's easier said than done with today's service providers.
Current Workarounds

The preceding scenario is made possible by two techniques that are seeing increased adoption: Embedding a script-based application or gadget from another domain using inline scripts in personalized Web pages, and embedding the gadgets in IFRAME elements.

Source : MSDN