Change Javascript frameworks on demand

I am new to web development. I am a C++ developer. I worked on a project where we were using different graphics libraries. Based on the systems environment variable we decide which library to use. I want this kind of design where we can change Javascript framework based on some settings. As technology is changing very fast Can we design such a way that we can change frameworks used in our web application will easily changeable? Is there any tool which can handle this or a design/architecture we can follow to achieve this.