Recursion is helpfule when traversing a tree: var b = { a : 'aa', c : { d : 'dd' } }; function deep ( value ) { var type = value === null ? 'null' : typeof value; if( type === 'object' ) { for( var prop in value ) { deep( value[ prop ] ); } } } Exercise 1: Add someting to the body of function to display object's tree. Tip: see comments in this code in html-page. Exercise 2: Console output is a bit rough. Let's stringify the object and show it. Add indent to nodes. Tip: see comments: