SuperMap Software Co., Ltd. introduces their JavaScript client library called SuperMap iClient for JavaScript. The library provides client-side GIS application development capabilities and acts as a unified JavaScript client for consuming SuperMap's cloud services and online maps. The document compares several popular open-source JavaScript mapping libraries such as Leaflet, OpenLayers, and MapboxGL that can be used with SuperMap iClient for visualization and mapping. Examples are provided showing how different mapping and visualization libraries can be combined.