The form on the left edits the XML document displayed on the right. Each input field of the form matches an attribute or element of the document.
The XML document must contain a sequence of elements number with an attribute negative whose boolean value tells whether the element contains a negative or positive integer. Edit an attribute or element in the form, and see what happens!
To use another schema, change the simplified Relax NG grammar that sits in the box on the left, and likewise with the box on the right for the XML document itself. Then press the Update button to refresh the editor.