jQuery Grid Plugin - jqGrid

I have a 2 buttons with following JavaScript oncLick function calls:

SearchByDebitDate(false) – do search by debit date. (search button)

SearchByDebitDate(true) – clear previous search. (clear button)

Here is a function's body:

function SearchByDebitDate(isClear)
  {

    var dtFrom = document.getElementById('<%=edDebitDateFrom.ClientID%>');
    var dtTo = document.getElementById('<%=edDebitDateTo.ClientID%>');

    if (isClear) {
      dtFrom.value = '';
      dtTo.value = '';    
      jQuery(”#report”).removePostDataItem(dtFrom);
      jQuery(”#report”).removePostDataItem(dtTo);
    }
    else
    {
      jQuery(”#report”).setPostData({ dtFrom: dtFrom.value, dtTo: dtTo.value });
    }
   
    jQuery(”#report”).trigger('reloadGrid');   
  }

1. I click “Search” button. Additional parameters will added to Ajax request.

2. When I click “Clear” button jqGrid creates an Ajax request. On server side I can still see in request query string unremoved two parameters dtFrom and dtTo.

It is a bug of jqGrid or a bug with my brain?

p.s. I have a latest 3.6.2 version of jqGrid, 1.3.2 verison of jQuery and 1.7.2 version of jQuery-ui.

pp.s. Sorry for my bad English 🙁

Thanks.