This mobile-compatible, responsive map includes clickable states, region zooming, U.S. territories and location markers. When loading the Maps JavaScript API, substitute YOUR_API_KEY in the code below with your API key. Map.has() Method in JavaScript The Map.has() method in JavaScript is used to check whether an element with a specified key exists in a map or not. It returns a boolean value indicating the presence or absence of an element with a specified key in a map. Interactive JavaScript Map Libraries amMap (by amCharts) amMap is a special JavaScript (HTML5) library for maps developed by amCharts. Google Maps JavaScript API error: MissingKeyMapError; For web developers: If you have access to the source code of your application, look for the