function merge(obj) {
    for (var i=1; i < arguments.length; i++) {
      var def = arguments[i]
      for (var n in def)
        if (obj[n] === undefined) obj[n] = def[n]
    }
    return obj
  }
function merge(obj) {
    for (var i=1; i < arguments.length; i++) {
      var def = arguments[i]
      for (var n in def)
        if (obj[n] === undefined) obj[n] = def[n]
    }
    return obj
  }
function merge ( obj ) { for ( var i = 1 ; i < arguments . length ; i ++ ) { var def = arguments [ i ] for ( var n in def ) if ( obj [ n ] === undefined ) obj [ n ] = def [ n ] } return obj }
Fills in default values.
Fills in default values .