jqGrid: Form isn't showing checkbox values - jqgrid

Question

I have the following call to load a grid:
$("#searchlist").jqGrid({
url:'./searchlibrary',
datatype: 'json',
mtype: 'POST',
postData: {
type: function(){return $('select[name="searchtype"]').val();},
criteria: function(){return getSearchData();}
},
colNames:['Resource Name','Unit', 'Topic','Document Type','Content Type','Select'],
colModel :[
{name:'resourceName', index:'resourceName', width:380, align:'left'},
{name:'unit', index:'unitID', width:40, align:'center',sortable:true,
sorttype:'text'},
{name:'topic', index:'topicID', width:220, align:'center',sortable:true},
{name:'docType', index:'docTypeID', width:97, align:'center',
sortable:true},
{name:'contentType', index:'contentTypeID', width:97, align:'center',
sortable:true},
{name: 'select', width:55, align: "center", sortable: false, editable: true,
edittype: "checkbox", editoptions: { value:"Yes:No" },
formatter:"checkbox",formatoptions: {disabled : false}}
],
rowNum:20,
sortname: 'resourceName',
sortorder: 'asc',
viewrecords: true,
gridview: true,
width:878,
height:251
});
Notice the last item in the colModel section. Notice the editoptions section. When the grid is loaded it seems to be ignoring this. Checking the element in chrome shows the following code being generated:
<input type="checkbox" value=" " offval="no">
Am I doing something wrong in the declaration?
UPDATE
Here's the JSON returned:
{"total":1,"page":"1","records":"4","rows":[{"id":"1","cell":["Test Resource 1","1","Topic 1","pdf","course","1"]},{"id":"2","cell":["Test Resource 2","1","Topic 1","pdf","course","2"]},{"id":"3","cell":["Test Resource 3","1","Topic 2","mp4","course","3"]},{"id":"4","cell":["Test Resource 4","1","Topic 2","wmv","course","4"]}]}
This still gives me 4 results all checked by default. This is what's in my colModel for select now:
{name: 'select', index:'resourceID', width:55, align: "center", sortable: false, editable: true, edittype: "checkbox", editoptions: { value:"Yes:No", defaultValue:"No" }, formatter:"checkbox",formatoptions: {disabled : false}}
The first generated html for one of the select cells is this:
<input type="checkbox" checked="checked" value="1" offval="no">

Answer 1

If you loads the data in the grid the values for the select column will be filled as the checkbox with respect of the formatter:"checkbox". If the value is "" the default value can be used. So one can use defaultValue of the formatoptions to specify the default value. The HTML fragment
<input type="checkbox" value=" " offval="no">
with " " value shows that you have probably wrong data with the space instead of empty string. If you need to fill the data correctly you need return from the server the data having true, false, 1, 0, yes, no, on or off (the case of all values are not important). See the source code for more details.
So you should one more time verify your data returned from the server. I personally prefer to use 1 and 0 as the input values for checkboxes.