code: function(containerID, options) {
          OpenLayers.Renderer.prototype.initialize.apply(this, arguments);
          this.root = document.createElement("canvas");
          this.container.appendChild(this.root);
          this.canvas = this.root.getContext("2d");
          this.features = {};
          if (this.hitDetection) {
              this.hitCanvas = document.createElement("canvas");
              this.hitContext = this.hitCanvas.getContext("2d");
          }
      }
docs: Constructor: OpenLayers.Renderer.Canvas
  
  Parameters:
  containerID - {<String>}
  options - {Object} Optional properties to be set on the renderer.