In recent years, many GIS applications have appeared on the Web giving users access to both spatial and non-spatial (attribute) data. However, a challenging task of Vector Active Map formats with such large volumes of online spatial data is that, in order to display them in most web browsers, either a plug-in has to be installed or an applet has to be downloaded. In this paper, a web service is proposed whose functionality enables the transformation of vector active maps from SVG to a new DHTML Active Map Representation, improving remote accessibility of spatial data. This new representation includes a raster representation of the map and a vector representation of its geographic objects. The former is used as a background image of the map whereas the latter enables the response to user-triggered events. A multi-level R-tree spatial index structure is used to access the geographic objects affected by each event in order to execute the relevant action.