How to realize data deduplication during pull-up refresh and pull-down load?

  html5, question

At present, there is a webView that needs to load data with ten articles and ten articles, but the problem cannot be repeated.

Generally, according to the unique number (such as ID) of the data, the data already in the list are compared and the data already in the list are eliminated before being added to the list.
If the list is updated frequently (e.g. high frequency UGC information), it is recommended not to use paging to obtain it, but to obtain the items after or before the last or the most previous item number, so as not to remove the weight, and also to avoid removing the whole page when the weight is removed too quickly.