How to set default filter in Grid

[GoogleCodeExporter]

Please let me know where I made mistake in the following code for setting 
default filter in grid search.

Code:
$.subscribe('searchgrid', function(event,data) {    
            $("#gridtable").jqGrid('searchGrid', {sopt:['cn','bw','eq','ne','lt','gt','ew'], 
                    multipleSearch: true,showQuery: true,
                    closeAfterSearch:false,
                    loadDefaults: true,
                    postData:{filters:'{"groupOp":"AND","rules":[{"field":"SUPPLIER_NM","op":"cn","data":"A"}]}'}           
                    } );            
        }); 

Original issue reported on code.google.com by vasantra...@gmail.com on 12 Oct 2012 at 10:11

[GoogleCodeExporter]

Along with above code below find the Grid Parameter setting

<sjg:grid id="gridtable" caption="%{getText('menu.suppliersearch')}" 
dataType="json" 
                href="%{listurl}"
                gridModel="liMs_SUPPLIERSs"
                width="300"
                autowidth="true"

                pager="true" 
                pagerInput="true"
                pagerPosition="center"  
                rowList="15,30,50"
                rowNum="15"
                rownumbers="true"
                viewrecords="true"

                onSelectRowTopics="rowselect"
                reloadTopics="reloadItems"

                draggable="true"

                navigator="true"
                navigatorAdd="false"
                navigatorEdit="false"
                navigatorRefresh="false"
                navigatorSearch="false"
                navigatorDelete="false"
                navigatorSearchOptions="{showQuery: false,multipleSearch: true}"

                navigatorExtraButtons="{                            
                            hide : { 
                                title : 'Show/Hide', 
                                icon: 'ui-icon-wrench', 
                                topic: 'showcolumns'
                            }                                       
                        }"
                >

Original comment by vasantra...@gmail.com on 12 Oct 2012 at 10:15