var VectorCanvas = function (width, height, params) {
  this.mode = window.SVGAngle ? 'svg' : 'vml';
  this.params = params;

  if (this.mode === 'svg') {
    this.createSvgNode = function (nodeName) {
      return document.createElementNS(this.svgns, nodeName);
    };
  } else {
    try {
      if (!document.namespaces.rvml) {
        document.namespaces.add('rvml', 'urn:schemas-microsoft-com:vml');
      }
      this.createVmlNode = function (tagName) {
        return document.createElement('<rvml:' + tagName + ' class="rvml">');
      };
    } catch (e) {
      this.createVmlNode = function (tagName) {
        return document.createElement('<' + tagName + ' xmlns="urn:schemas-microsoft.com:vml" class="rvml">');
      };
    }

    document.createStyleSheet().addRule('.rvml', 'behavior:url(#default#VML)');
  }

  if (this.mode === 'svg') {
    this.canvas = this.createSvgNode('svg');
  } else {
    this.canvas = this.createVmlNode('group');
    this.canvas.style.position = 'absolute';
  }

  this.setSize(width, height);
};

VectorCanvas.prototype = {
  svgns: 'http://www.w3.org/2000/svg',
  mode: 'svg',
  width: 0,
  height: 0,
  canvas: null
};