Firstly i found a logic to customize or extends Openlayers 2 Control Navigation. I dont want to custom the openlayers default, because I'm currently using 2 different map in one page. especially to custom after panning or zooming.
The purpose is I Whenever user after panning/zooming/wheel-zoom or the position/zoom of first map is change, it can get latests 4 LatLon of corner side from frame viewed first map then call a function to process it.
edit: already found a way using event register