javascript: optional first argument in function

You have to decide as which parameter you want to treat a single argument. You cannot treat it as both, content and options.

I see two possibilities:

1. Either change the order of your arguments, i.e. function(options, content)

2. Check whether options is defined:

   function(content, options) {
       if(typeof options === "undefined") {
           options = content;
           content = null;
       }
       //action
   }
   

   But then you have to document properly, what happens if you only pass one argument to the function, as this is not immediately clear by looking at the signature.