function Element(domElement) {

      // Helpers
      this.attr = function(attrName) {
        return domElement.getAttributeNS(null, attrName);
      };

      // Properties
      this.tag = domElement.tagName;
      this.class = this.attr('class');
      this.id = this.attr('id');

      // Methods
      this.isNode = function() {
        return !!~this.class.indexOf(self.settings('classPrefix') + '-node');
      };

      this.isEdge = function() {
        return !!~this.class.indexOf(self.settings('classPrefix') + '-edge');
      };

      this.isHover = function() {
        return !!~this.class.indexOf(self.settings('classPrefix') + '-hover');
      };
    }
This helper will bind any DOM renderer (for instance svg)
to its captors, to properly dispatch the good events to the sigma instance
to manage clicking, hovering etc...

It has to be called in the scope of the related renderer.