A preview system enables an administrator or designer of portal content to preview changes made to one or more documents in a portal. Upon modification of a document in the portal, a preview document is generated. The preview document utilizes a main portal archive for content, but the locally modified files for presentation elements. The preview document includes instructions such, that when it is viewed in a web browser, it can present the identity of style properties influencing a presentation of an area in the document by selecting the area.