code: function appendSpy(child) {
          // ignore appending to the node that's not yet added to DOM tree
          if (!this.parentNode) {
              return;
          }
  
          var destNodePath = phantomas.getDOMPath(this),
              appendedNodePath = phantomas.getDOMPath(child);
  
          // skip undefined nodes (issue #560)
          if (destNodePath === false) {
              return;
          }
  
          // don't count elements added to fragments as a DOM inserts (issue #350)
          // DocumentFragment > div[0]
          if (destNodePath.indexOf('DocumentFragment') === 0) {
              return;
          }
  
          phantomas.incrMetric('DOMinserts');
          phantomas.addOffender('DOMinserts', {append: appendedNodePath, node: destNodePath});
  
          phantomas.log('DOM insert: node "%s" appended to "%s"', appendedNodePath, destNodePath);
      }
docs: count DOM inserts