商品的无线详描是一个json字符串，包含三个字段
示例
{
"mobileDetail": [
{
"content": "line 1",
"type": "text"
},
{
"content": "line 2",
"type": "text"
},
{
"col": 1,
"images": [
{
"imgUrl": "http://ae01.alicdn.com/kf/1.jpeg"
}
],
"type": "image"
},
{
"content": "line 4",
"type": "text"
},
{
"col": 2,
"images": [
{
"imgUrl": "http://ae01.alicdn.com/kf/2.jpeg"
},
{
"imgUrl": "http://ae01.alicdn.com/kf/3.jpeg"
}
],
"type": "image"
},
{
"content": "line 6",
"type": "text"
}
],
"version": "1.0",
"versionNum": 1
}