This type of initialization means that some layout's cell will be made the parent for the newly created layout.
If you want to carry out this kind of initialization - make the following steps:
1. Create a new dhtmlXLayoutObject.
var dhxLayout = new dhtmlXLayoutObject("parentId", "3L", "dhx_black");
2. When the dhtmlXLayoutObject will be created, specify its parent either through cells or through items:
var Layout1 = new dhtmlXLayoutObject(dhxLayout.cells("a"), "2U"); // OR var Layout1 = new dhtmlXLayoutObject(dhxLayout.items[1], "2U");