identifyParams.layerIds = dynamicMapServiceLayer.visibleLayers;
function getVisibleLayers() { var visibleLayers = [];
var items = dojo.map(dynamicMapServiceLayer.layerInfos, function (info, index) {
layerID = info.id;
if (info.visible && !info.subLayerIds) {
visibleLayers.push(layerID)
}
}); return visibleLayers
}