Calling a Java function with a JavaScript variable inside a JavaScript function

I need help. I need to call a Java function "getLocCountByWhId()" in a Java class; this Java function is being called within a JavaScript in a for-loop. I need to pass in a JavaScript variable as a parameter into this Java function "getLocCountByWhId()". I have been struggling for a week and reading numerous website to get some guidelines but I have not been able to resolve the problem. Thank you in advance for your help. The code is listing below:

<script language="JavaScript">
<!--
function onCreatePO()
{
    <%long jspAllocId = alloc.getId();%>;
    var recItemId = ""; // Local variable for item id.
    var recWhId = ""; // Local variable for warehouse id.                           

    for (var i=0, j=document.what_if_summary.elements.length; i<j; i++)
    {      
       var recStr = document.what_if_summary.elements[i].value; 
       var splitStr = new Array(); 
       splitStr = recStr.split('^');
       recItemId = splitStr[1]; // Get the field value for Item_ID.
       recWhId = splitStr[2]; // Get the field value for Warehouse_ID.

// Get a database connection with global 'conn' object and retrieve store count.
       <%AfsGetVDSCountByWarehouseBean.setConnection(conn);%>; 

// The below assignment from JavaScript variable to JSP variable do not work 
// because of a second JavaScript tag. How can I get around this ?

//<% String jspItemId = "<script>document.writeln(recItemId)</script>"; %>
//<% String jspWhId = "<script>document.writeln(recWhId)</script>"; %>

   currentStoreCount = <%= AfsGetVDSCountByWarehouseBean.getLocCountByWhId(jspAllocId, jspItemId, jspWhId)%>;
   }
}

//-->
</script>

// I get this example of assigning Javascript to JSP variable but I got double tag problem.
<script>
var v="Roseindia";
</script>
<% String st="<script>document.writeln(v)</script>";
out.println("value="+st); %>