popup issue for showModalDialog

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.NET2.0

Javascript

.NET

jQuery

, +

Scenario is I have one parent and on child page. Child page contain list of say countries. I was using showModalDialog function in java script which is easily returned the value I had selected in my child page. Recently this functionality is not working in chrome as in new update they have deprecated showModalDialog function. Please suggest me some alternative to achieve this.
I tried same using different methods but issue I am facing is there are multiple values returning from child which I have to split and assign to my hidden values in parent:
This is my Parent code:

function Display_Session_Year(obj,obj_desc,Steps)
       {
           var retVal;
           strPage = "PopUpHelper.aspx?PageName=Pop_Commodity_warehouse_session.aspx&Steps=" + Steps;
           DialogWidth="dialogWidth:500px; dialogHeight:550px;Center:yes; scroll:yes ;resizable:no;status:no;";
           retVal=window.showModalDialog(strPage,'',DialogWidth);
           if(retVal!="" && retVal!=null)
           {

               var ArrValues=retVal.split("~")


               document.getElementById(obj).value = ArrValues [0];
               document.getElementById(obj_desc).value = ArrValues [1];
               document.getElementById('<%=txt_seasonyearDesc.ClientID%>').value = ArrValues [3];
            //document.getElementById(obj_desc).focus();
          document.getElementById('<%=txt_seasonyearDesc.ClientID%>').focus();
        }
    }

This is child page code:

function Returnval(Val)
        {
         top.returnValue= Val
        parent.window.close();
    }