When working with vector layers, styling is a great feature which offers us a lot of possibilities: fill color and opacity, stroke color, labels and text colors, and so on. But, what if we need more?
OpenLayers.Layer.Vector instance contains a renderer that is responsible to render the layer's features (such as points, paths, and polygons) on the map using the best technologies available in the browser. These can be the HTML5 Canvas element (http://en.wikipedia.org/wiki/Canvas_element) available in many modern browsers (such as Firefox or Chrome), SVG (http://en.wikipedia.org/wiki/Scalable_Vector_Graphics), or VML (http://en.wikipedia.org/wiki/Vector_Markup_Language).
OpenLayers.Layer.Vector is initialized, ...