var json2 =({
  "?xml": {
    "@version": "1.0",
    "@encoding": "UTF-8"
  },
  "text": {
    "heading1": {
      "@fieldnumber": "0",
      "#text": "目的"
    },
    "objective": {
      "@fieldnumber": "1",
      "#text": "学习什么是力以及它们的作用。"
    },
    "heading2": {
      "@fieldnumber": "2",
      "#text": "总结"
    },
    "summary": {
      "@fieldnumber": "3",
      "#cdata-section": "&#187;  力是一个物体对另一个物体的作用。\n<br>&#187;  力可被测量，单位为牛顿（N）。\n<br>&#187;  力改变物体的运动状态和形状。\n<br>&#187;  重力是万有引力产生的把物体向下拉至地心的力。"
    }
  }
});
