怎么判断从网页读取的数据是否刷新了？：报错

如果每次读取的数据很多的话类似：

{"result":"true","data":[{"date":"1398348450","price":3088,"amount":0.8039,"tid":"7180798","type":"sell"},{"date":"1398348517","price":3085,"amount":0.8253,"tid":"7180825","type":"sell"},{"date":"1398348533","price":3084.19,"amount":0.0309,"tid":"7180828","type":"sell"},{"date":"1398348538","price":3084.19,"amount":0.039,"tid":"7180831","type":"sell"},{"date":"1398348603","price":3086.17,"amount":0.0176,"tid":"7180841","type":"sell"},{"date":"1398348697","price":3088,"amount":0.1631,"tid":"7180863","type":"buy"},{"date":"1398348702","price":3085.4,"amount":0.0601,"tid":"7180868","type":"sell"},{"date":"1398348707","price":3085.4,"amount":0.0697,"tid":"7180871","type":"sell"},{"date":"1398348712","price":3085.4,"amount":0.0526,"tid":"7180873","type":"sell"},{"date":"1398348807","price":3085.41,"amount":0.6088,"tid":"7180911","type":"sell"},{"date":"1398348818","price":3085.41,"amount":0.002,"tid":"7180913","type":"sell"},{"date":"1398348829","price":3088,"amount":0.0063,"tid":"7180916","type":"buy"},{"date":"1398348839","price":3088.1,"amount":0.0501,"tid":"7180923","type":"buy"},{"date":"1398348930","price":3086.41,"amount":0.1079,"tid":"7180943","type":"sell"},{"date":"1398348962","price":3089.2,"amount":0.0185,"tid":"7180948","type":"sell"},{"date":"1398348972","price":3090,"amount":0.031,"tid":"7180951","type":"buy"},{"date":"1398348983","price":3090,"amount":0.051,"tid":"7180959","type":"buy"},{"date":"1398348993","price":3090,"amount":0.0027,"tid":"7180961","type":"buy"},{"date":"1398348993","price":3091,"amount":0.0466,"tid":"7180963","type":"buy"}],"elapsed":"0.752ms"}

每次改变的也许只是其中的一笔数据或者两笔数据，难不成还要全部对比所有的数据？这不是很麻烦？

######

MD5下字符串  每次比较MD5后的结果

######为什么要MD5呢？我直接比较字符串不行么？######+1###### +1######

从页面抓取过来应该是序列化的json吧，直接对比字符串不行嘛？ 如果是对象格式，用JSON.stringify序列化一下再对比。

顺便问下楼主，如果data数组里面两个元素交换了顺序，算不算是数据变化呢？如果这种不算数据变化，那任何对比字符串的方式都白瞎了

######这里面的数据是会更新的，会返回最新的几十笔交易数据，若我每10秒读取一次，数据有可能全部刷新，有可能部分跟新，还有可能不变。。但是我需要每次读取将数据存储起来，存储起来的是新数据，以前存过的便不用存了。。但是每一个判断准则，所以好头疼。######

做两种查询

一种结果里面带个"update time",返回个时间戳

一种是这种查询整套数据的

从流量和响应来说都好

######回复 @登峰 : 两种查询.一种是查询数据最新更新时间,如果后端前端一致就不必发送获取更新数据的请求. 否则如果有更新则从另外一种查询返回更新过的整套数据, 不是返回所有数据.######查询整套数据？这样不太现实吧，要是我已经存储的数据量很大呢？时间间隔太小，几秒钟刷新读取一次，用时间戳没什么用吧。###### 嗯，这个对读取的是一笔数据时比较容易判断的。