It also allows you to avoid using too many timers! This is important: each timer is a callback.
Each callback executes JS code. While JS code is executing, browser events - including other callbacks - are delayed or dropped.
When the callback finishes, additional callbacks must compete with other browser events for a chance to execute. Therefore, one timer that handles all pending tasks for that interval will perform better than two timers with coinciding intervals, and (for short timeouts) bett...
원문 링크 : javascript setTimeout web
