code: function(canvas, node, controller) {
        var id = node.id, tag = this.getLabel(id);
        if(!tag && !(tag = document.getElementById(id))) {
          var ns = 'http://www.w3.org/2000/svg';
            tag = document.createElementNS(ns, 'svg:text');
          var tspan = document.createElementNS(ns, 'svg:tspan');
          tag.appendChild(tspan);
          var container = this.getLabelContainer();
          tag.setAttribute('id', id);
          tag.setAttribute('class', 'node');
          container.appendChild(tag);
          controller.onCreateLabel(tag, node);
          this.labels[node.id] = tag;
        }
        this.placeLabel(tag, node, controller);
      }
docs: /*
  Method: plotLabel
  
  Plots a label for a given node.
  
  Parameters:
  
  canvas - (object) A <Canvas> instance.
  node - (object) A <Graph.Node>.
  controller - (object) A configuration object.
  
  Example:
  
  (start code js)
  var viz = new $jit.Viz(options);
  var node = viz.graph.getNode('nodeId');
  viz.labels.plotLabel(viz.canvas, node, viz.config);
  (end code)