Found the solution, using the beforeRequest, im appending the extra criterium this way the first request takes also

the filter data:

config.beforeRequest = function()

{
    if (!$(this).getPostDataItem('filters'))
    {
        $(this).appendPostData({"filters":"{"groupOp":"AND","rules":[{"field":"test","op":"bw","data":"asdf"}"});
    }
};

Im also using an cookie to set the data when filtering and echoing the cookie (im using php)

with appendPostData(<?php echo $_COOKIE['filterthing'] ?>) so it will result to:

{"filters":"{"groupOp":"AND","rules":[{"field":"test","op":"bw","data":"asdf"}"}

$('#testinggrid').filterToolbar({
        autosearch: true,
        searchOnEnter: false,
        stringResult:true,
        beforeSearch: function()
            {
                $.cookie('filterthing', JSON.stringify($('#testinggrid').getGridParam('postData')));
            }
    });

You will need the jquery cookie plugin to use this way with the cookie or get some other javascript cookie thing

if you want to remeber the user input in the filter columns, if not the onbeforeRequest thing is the only thing you'll

need.

getGridParam will return an object so you need to set it to a string or set an object cookie.

Im having some weird issue, i have put the this in the colmodel {name: 'test', index: 'test', search : 'true', stype: 'text', searchoptions: { defaultValue: 'asdfasf'}}

when the grid loads the data (ajax call) it doesn't uses the defaultValue and the field for the filters

var config = {
"url:"http://theurl",
"datatype":"json",
"colNames":["test"],
"colModel":[ {"name":"test","index":"test","search":true,"stype":"text","searchoptions":{"defaultValue":"asdfasdf"}} ],
"rowNum":10,
"rowList":[10,20,30],
"pager":"pager",
"sortname":"test",
"viewrecords":true,
"sortorder":"asc",
"height":"100%",
"autowidth":true,
"viewsortcols":[false,"horizontal",true],
"filterable":true,
"imgpath":"js",
"search":true,
"jsonReader":{"repeatitems":false,"id":"0"}
};

$('#testingrid').jqGrid(config);
$('#testingrid').filterToolbar({
                    autosearch: true,
                    searchOnEnter: false,
                    stringResult:true,    
                    });

The url will give this: http://theurl?something&_s.....p;sord=asc

instead of:

http://theurl?something&_s.....D%2C%7B%22

Does someone know how to use the default value in the filters when the grid loads for the first time.

Thanks!

Greets