Recursive functions

I am using the following code which recursively executes function findWpisInZone(), code works fine, I just wondering if there is any better way to do it in JS,

DomBuilder.prototype = {
            domTree: '',
            findWpis: function () {
                var dataState = dojo.global.xxx.state.data,
                    scope = this;
                for (var zone in dataState) {
                    for (var wpi in dataState[zone]) {
                        this.domTree += '<div data-xxx-type="{0}">'.format(zone);
                        findWpisInZone(dataState[zone][wpi]);
                        this.domTree += '</div>';
                    }
                }
                function findWpisInZone(wpi, type) {
                    scope.domTree += '<div data-xxx-type="{0}">'.format(wpi.wpi.webpart_cid);
                    for (var zone in wpi.zones) {
                        scope.domTree += '<div data-xxx-type="{0}">'.format(zone)
                        for (var wpiInner in wpi.zones[zone]) {
                            // recursion search
                            findWpisInZone(wpi.zones[zone][wpiInner], type);
                        }
                        scope.domTree += '</div>';
                    }
                    scope.domTree += '</div>';
                }
            },