crm 2011 JS: Get and Set lookup value using javascript in CRM 2011

//This is how to Get and Set lookup value using javascript in CRM 2011  

Get a lookup value
var lookup = new Array();
lookup = Xrm.Page.getAttribute("attributename").getValue();
if (lookup != null) {
    var name = lookup[0].name;
    var id = lookup[0].id;
    var entityType = lookup[0].entityType;
}

Set a lookup value
var lookup = new Array();
lookup[0] = new Object();
lookup[0].id = recorid;
lookup[0].name = recordname;
lookup[0].entityType = entityname;
Xrm.Page.getAttribute("attributename").setValue(lookup);

Alternate method to set lookup value
Xrm.Page.getAttribute("attributename").setValue([{ id: recorid, name: recordname, entityType: entityname}]);