Techniques for forming a document model for constructing a semantically and syntactically valid document are provided. In one embodiment, a method for forming a document model for constructing a semantically and syntactically valid document includes the steps of: creating a root tag element corresponding to a root of the document to be constructed, the root tag element including information relating to a corresponding tag; associating one or more model elements with the root tag element, each model element representing an alternative to the information relating to the corresponding tag; and for each of the model elements, creating a syntactically and semantically valid sub-tree of elements based at least in part upon a structure of the document to be constructed under one or more predetermined conditions.