Exporting string to file w/ double quotes

Exporting string to file w/ double quotes

I'm trying to write a string to variable & then write that to a file, but the quotes are coming in as "  I've tried several things & not having success.

Currently have this:
  1. var keystring = "$easydb->key="" + usersalt + "";";

Which yields the following string in the file:  

  1. $easydb->key="GN86rI4pZ5ggGGjp";

I want it to end up as: 

  1. $easydb->key="GN86rI4pZ5ggGGjp";

So how do I write it to get those double quote to actually show in the file?