How do I get my screen light to stay on when on a wall charger for my iphone 5?

I have never heard of this being possible. Scanned through my settings and didn't find anything that would do what you ask.

Settings>General>Auto-Lock>Never.

Be sure to change that once you remove from the charger, or you'll be measuring your battery life in minutes.

Nice work around but I agree, forgeting to disable that after disconnecting from the charger would be bad for the battery life. I can't imagine leaving the screen lit the whole time would be good for the LCD or LED backlight either.

Not a "work-around" at all, rather an iPhone setting that accomplishes exactly what the OP wants, and other than running the battery dry, will do no harm.

You're welcome.

With all due respect, that IS a work around which does give him NEARLY everything he wants as it does not only do it while he is plugged into the charger and requires manual intervention to disable each and every time he charges and disconnects. Still a nice work around.

Take care,

Fred