Set the value to lookup control

In the form if you want to set/assign value to the look-up control.

var objLookup = new Array();

objLookup[0] = new Object();

objLookup[0].id = id;

objLookup[0].name = name;

objLookup[0].entityType = entityType;

//set value of look up

Xrm.Page.getAttribute( "new_pricelist_lookup" ).setValue(objLookup);

Suppose if the error occurs while assign a value to the lookup control

Error: The request should be a valid top-level resource object.

Then you have to look that value(objLookup) is not proper array object to assign to the lookup control.

check entity type and name of the array object