How to set a Lookup Field to another Lookup Field using JavaScript in Dynamics 365 CRM

Populate Lookup Based on Selection of Another Lookup

Create 2 lookup fields in your Form

i have created lookup1 and lookup2

Next,

Create web resource with the below code

function LookupValue(executionContext){
var formContext = executionContext.getFormContext();
var lookupvalue1= formContext.getAttribute(“test_lookup1”);
if (lookupvalue1 != null) {
var lookup = lookupvalue1.getValue();
if ((lookup != null)) {
if (lookup[0].id != null) {
var lookup1 = new Array();
lookup1[0] = new Object();
lookup1[0].id = lookup[0].id;
lookup1[0].name = lookup[0].name;
lookup1[0].entityType = lookup[0].entityType;
formContext.getAttribute(“test_lookup2”).setValue(lookup1);
}

}
}
}

Go to Form editor —> Select lookup1 field properties —> Click Events –> Add the Web Resource with the above code