Passing content of server-side text file to variable in *.js

Question

I am using WebIOPi to create a program to control GPIO on a raspberry pi. I cannot use PHP as it conflicts with WebIOPI. I am altering the webiopi.js. I have it 99% there for my needs but I have to save two settings to the server. I decided to use a txt file to do this. Is it possible to place the single number in the txt file into the variable for use in the javascript? Is it possible to write to the text file?

var noThing;
checkThingNumber = function(){

noThing = thingNumber.txt;

return noThing;
}