The Chrome Intersection Observers API allows developers to determine when an element in their DOM is visible to the end user. If an element is only partially visible, the API can determine what proportion of it is visible. This could be used to delay loading images until they're needed or to determine whether an end user is actually seeing an ad banner.
The following is a list of SDKs from our SDK directory that matched your search term. Though your definition of an SDK may differ, in our world, we define SDKs as platform- specific tools for consuming existing APIs of the sort we list in our API directory. For example, the Ruby SDK for consuming the Twitter Ads API. If you think an SDK, API, or other asset is missing from our directory, be sure to check our guidelines for making contributions to ProgrammableWeb.