code: function valueInViewScope(node, value, tag) {
          var min, max;
          var pos = getPosition(node);
          viewScope = {
              start: {left: pos.left, top: pos.top},
              end: {left: pos.left + node.clientWidth, top: pos.top + node.clientHeight}
          };
          var str = tag == 1 ? 'left' : 'top';
          min = viewScope.start[str];
          max = viewScope.end[str];
          return (value >= min && value <= max);
      }
docs: Check target is in range
  @param node
  @param value
  @param tag
  @returns {boolean}