The Xopus API can be used to do almost anything. It requires some skills with Javascript, but it makes it possible to create extra functionality, or to assist user actions. When adding an example in this document, an API function is called to set an extra attribute that helps in rendering the example. To add this functionality, a few things are needed. First we need a beginning. We need to listen to when Xopus has finished loading. Editor.addEventListener("load",doLoad); Now we need a doLoad function to deal with the event. function doLoad(evt) { var doc = evt.document; doc.addEventListener("XopusAfterChildInserted", afterChildInserted); } A new eventListener is then added to the document. This listens to childNodes being inserted. function afterChildInserted(evt) { var node = evt.childNode; if(node.getNodeName() == "example") node.setAttributeNS("http://www.w3.org/XML/1998/namespace","xml:space","preserve"); } The xml:space attribute stops the above code example from collapsing whitespace. The evt argument contains openings to access data about the event. These events are documented on the Xopus website. The API can be used to do many things: Create extra buttons in the XSL for adding, removing or moving elements Setting a value for required attributes after element creation in order to prevent property panels from opening Setting unique ID's Changing properties of the Editor environment It can also be used to open the property panel: node.openAttributesEditor();