Shows how to use a StyleMap to style features with rule based styling. A style map references one or more OpenLayers.Style objects. These OpenLayers.Style objects are collections of OpenLayers.Rule objects that determine how features are styled. An OpenLayers.Rule object combines an OpenLayers.Filter object with a symbolizer. A filter is used to determine whether a rule applies for a given feature, and a symbolizer is used to draw the feature if the rule applies.
A style map is used with vector layers to define styles for various rendering intents. The style map used here has styles defined for the "default" and "select" rendering intents. This map also has an active select feature control. When you hover over features, they are selected and drawn with the style corresponding the the "select" render intent.