ColdFusion Read Mobile Device File and Write Mobile Device File - From Local Device

Question

I am trying to read a file that is stored locally on a mobile device. I'm having trouble knowing where to store it. Read/Write it from. Should the file be right with the config.xml or stored in the www area on device.

Ultimately the web app is being all served from webpages. But I want to store their login information to do auto logins really.

So read the file : logset.txt

I want to read it by and do a cflocation for auto login:

<cfset fc = #fileRead(expandPath("/logset.txt"), "utf-8")#>

Then if no login settings. Present them a form and write the file, then cflocation to login.

<cfset fpath = expandpath('\')>

<CFFILE ACTION="Write"
  FILE="#FPath#logset.txt"
  nameConflict="overwrite"
  OUTPUT="#nf#">

This all works on the web. But I need it to write the local file to the device and read it from the device. Path issue is what I need sorted I guess.