Passing JSON object name into function with Javascript
===

I'm looking to pass a string into a function and return the json object of that string name.

Objname is a string, such as "ky1"
    
    function myFunction(objname) {
        return myjsonobj.objname;
    }

How can I get the above to parse correctly? 
This is a simplified example, but demonstrates what I'm trying to achieve.

I'm not using jQuery, this is not an option for me in this piece of work.

Any help would be great, thanks!