how to do to make sure phonegap js load just once time in an app with many separate pages?

Use phonegap 1.6,now called cordova 1.6, with jquery mobile 1.0.1,but I feel performance is a problem.
Also with some other js libs,such as iscroll.js, plus the performance problem.

Can I load phonegap js just once,and later all pages can still use phonegap api?

I have an idea that Page A load phonegap js ,and nested iframe refer Page B.
Page B will replace by other pages. Can Pages in iframe use its parent phonegap api?

eg: parent.(all phonegap api)

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