If the collection contains anything other than a single <svg> element, it will append the elements in the collection to a new <svg> container, crop the container to its contents and return the container.
If the collection already contains a single <svg> element, then it will just be returned.
This is useful for operations that need to work on an <svg> container and is used internally, for example by the dataUrl() and markup() methods.
var svg = Pablo.circle({r:50}).withViewport();
svg.appendTo(demoElement);
alert(svg[0].nodeName);