code: function createElement(el, attrs, children) {
  
          if (!el) return undefined;
          
          // If `el` is an object, it is probably a native SVG element. Wrap it to VElement.
          if (typeof el === 'object') {
              return new VElement(el);
          }
          attrs = attrs || {};
  
          // If `el` is a `'svg'` or `'SVG'` string, create a new SVG canvas.
          if (el.toLowerCase() === 'svg') {
              
              attrs.xmlns = ns.xmlns;
              attrs['xmlns:xlink'] = ns.xlink;
              attrs.version = SVGversion;
              
          } else if (el[0] === '<') {
              // Create element from an SVG string.
              // Allows constructs of type: `document.appendChild(Vectorizer('<rect></rect>').node)`.
              
              var svg = '<svg xmlns="' + ns.xmlns + '" xmlns:xlink="' + ns.xlink + '" version="' + SVGversion + '">' + el + '</svg>';
              var parser = new DOMParser();
              parser.async = false;
              var svgDoc = parser.parseFromString(svg, 'text/xml').documentElement;
  
              // Note that `createElement()` might also return an array should the SVG string passed as
              // the first argument contain more then one root element.
              if (svgDoc.childNodes.length > 1) {
  
                  return _.map(svgDoc.childNodes, function(childNode) {
  
                      return new VElement(document.importNode(childNode, true));
                  });
              }
              
              return new VElement(document.importNode(svgDoc.firstChild, true));
          }
          
          el = document.createElementNS(ns.xmlns, el);
  
          // Set attributes.
          for (var key in attrs) {
  
              setAttribute(el, key, attrs[key]);
          }
          
          // Normalize `children` array.
          if (Object.prototype.toString.call(children) != '[object Array]') children = [children];
  
          // Append children if they are specified.
          var i = 0, len = (children[0] && children.length) || 0, child;
          for (; i < len; i++) {
              child = children[i];
              el.appendChild(child instanceof VElement ? child.node : child);
          }
          
          return new VElement(el);
      }
docs: Create SVG element. -------------------