An application on a computing device includes a digital ink system that supports the input and output of digital ink in a markup language document. Digital ink refers to a digital representation of object (e.g., pen or finger) strokes on an input device that can be displayed on an output device. The markup language document can include, for example, an edit box in which the digital ink and optionally other data can be input. As the input object moves over the input device, data identifying the locations of the input object are captured and embedded in a markup language element of the document. The digital ink system also allows documents including digital ink to be displayed, the digital ink system displaying the digital ink along with any other data included in the document.