get values of another item

hi ,

I am unable to get values that I am having to a relationship grid of parent item on the client side.

I have written this on a onClick event on the property. i am able to set source id and related id of item type, but after that unable to make relationship with next item type . related id and last item type id are same.

I am having cost as field in FM_Itemtype and doing their total of it in total cost in FM_formula item type using field event. 

I tried various ideas but cant getting success

Please help ..

here is my code

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innovator = document.thisItem.getInnovator();

var vFormula = innovator.newItem("FM_Formula","get");

var vFormulaId=document.thisItem.getProperty("id");

vFormula.setAttribute("where", "[FM_Formula].id='" + vFormulaId + "'");

vFormula.setID(vFormulaId);

var vFormulaBom = vFormula.newItem("FM_FORMULABOM","get");

vFormulaBom.setAttribute("select", "source_id");

vFormulaBom.setAttribute("select", "related_id");

var vItem = vFormula.newItem("FM_ITEM","get");

vItem.setAttribute("select", "id, cost");

vFormulaBom.setRelatedItem(vItem);

vFormula.addRelationship(vFormulaBom);

var results = vFormula.apply();

var count = results.getItemCount();

alert(count);

var v=0;

for (var i=0; i<count; i++)

{

var vIndexitem = results.getItemByIndex(i);

var vItem=vItem.getRelatedItem();

var  vCost = vIndexitem.getProperty("cost");

if (vCost)

{

v=parseFloat(v) + parseFloat(vCost);

 }

alert(vCost);

}

handleItemChange("total_cost", v);