🚀 go-pugleaf

If you don't already have, enable the JavaScript debugger somewhere at the top of your script:

$.level = 2;

Then if you again hit that error, examine the problem variable.
For example, try this expression:

typeof myPound

I suspect yours is something like undefined or null.
Without debugger / during execution you check it this way:

if( myPound ==null ) {
// the "==" operator catches both null and undefined
alert("bummer");
exit();
}

to get more specific info, try this:

var undefined; // intentionally not initialized
// the "==="operator checks for exact match
if( myPound ===null ) alert("null");
else if( myPound ===undefined ) alert("undefined");
else alert(typeof myPound);

Dirk