How to trigger an event for a dynamically referenced element Dojo

i could not triggerd an event to an referenced element.

here a snippest of my code:

 

       

var divcp= dojo.byId("dcp")  // "dcp": div-element  in the center region in main.html

var topcp   = registry.byId("tcp") //  BoderContainer/Top contentpane
var leftcp   = registry.byId("lcp") // BoderContainer/left 
var centercp = registry.byId("ccp") // BoderContainer center

var ntb= on(divcp, "click", function(evt){
centercp.set("href", "productA.html");  //take place in  center region of the BorderContainer
leftcp.set("href", "products.html");  //  list all product categories on the left region

});

now when i click a product category  on the left region of the BorderContainer i could not trigger the event


var pctB = dojo.byId("divproductB"); // divproductB is div-id in products.html file.

 var lpca = on(pctB, "click", function(evt){

centercp.set("href", "productB.html");

});

your contributions to solve my issue are highly apreciated.

many thanks