code: function getTransformToElement(target, source) {
              var matrix;
              try {
                  matrix = source.getScreenCTM().inverse();
              } catch(e) {
                  throw new Error('Can not inverse source element\' ctm.');
              }
              return matrix.multiply(target.getScreenCTM());
          }
docs: 由于新版chrome(dev 48.0)移除了getTransformToElement这个方法可能导致报错，这里做兼容处理
  @Date 2015-11-12
  @Editor Naixor