Sometimes we need information from our servers as soon as it’s available. The usual AJAX request/response we’re all used to doesn’t keep the connection open for this sort of use case. Instead, we need a push-based method like WebSockets, long polling, server-sent events (SSE), or, the more recently created, HTTP2 push. In this article, we compare two methods: WebSockets and long polling.
An Overview of Long Polling
In 1995, Netscape Communications hired Brendan Eich to implement scripting capabilities in Netscape Navigator and, over a ten-day period, the JavaScript language was born. Its capabilities as a language were initially very limited compared to modern-day JavaScript, and its ability to interact with the browser’s document object model (DOM) was even more limited. JavaScript was mostly useful for providing limited enhancements to enrich document consumption capabilities. For example, in-browser form validation and lightweight insertion of dynamic HTML into an existing document.