URL hacking to pre-populate dependent lookup field's data

Question

I have a case, where i need to pre-populate a lookup field's (lkp 2) data based on the record selected in another lookup field (lkp 1) in a custom object where lkp 1 and lkp 2 are two seperate custom object having 1: 1 relation ship.

I am able to display the data using formula field in text field based on selected value of lkp 1 ..But , If anyone can guide me how to use URL hijacking here to pre-populate lkp 2 value before saving the record of this custom object, would be grateful. TIA.

Answer 1

trigger myTrigger on ObjectA__c(before insert, before update){
    for(Object A obj : Trigger.new){
        if(obj.Lookupfield__c !=null){
            obj.secondLookUp = obj.LookupField__c;
        }
    }
}