WebAnno presents a flexible approach to the efficient and exhaustive manual annotation of text documents. WebAnno also allows adding and configuring an arbitrary number of layers through a web-based UI. These layers can be annotated separately or simultaneously, and support most types of linguistic annotations such as spans, semantic classes, dependency relations, lexical chains, and morphology. Further, WebAnno tightly integrates a generic machine learning component for automatic annotation suggestions of span annotations. You can follow the tuorials here.
To try WebAnno, login here with username guest and password guest. Create your own project/tagset and try all the functionality (chrome and safari browsers compatible). Source code with installation instructions and sample data is available here.