ECMAScript for XML is an objectification layer that makes it possible to treat XML as a native datatype. Implemented in Firefox and ActionScript (and likely to be implemented in most other browsers and many programming environments) E4X provides an alternative to the DOM for manipulation of XML data, and will likely become one of the focal points for development of Web applications in the future.

This paper looks at how the combination of E4X and AJAX makes it possible to significantly reduce the development time of AJAX applications, and explores how these can be combined with an alternative approach to object-oriented design principles within the client to make what was previously fairly formidible, the use of extensive DOM manipulation – radically simpler. This paper will also focus on how E4X can work with bound DOM systems (such as SVG and XUL), while still retaining both the flexibility of the former with the the power of the latter.