XMLHttpRequest::Open () The open method is used to set the request type (GET, POST, PUT or PROPFIND), the URL of the page being requested and whether the call will be asynchronous.

The Firebug Lite JavaScript suite replicates the most useful tools you'll find in the venerable Firebug add-on, including the console, command line interface and XmlHttpRequest inspector.

When manually writing and maintaining the XMLHttpRequest code, a developer must deal with many potential problems, especially with cross-browser compatibilities like different DOM implementations.