jQgrid: multiselect true - make each row checked b

jQuery("#grid").jqGrid({
    url:call_url,
        datatype: "json",
    height: 'auto',
    rowNum: 20,
    rowList: [20,30,40],
    colNames:[<?php echo $col;?>],
    colModel:[
                {name:'USER_ID',index:'USER_ID', align:'center',search:false,hidden:true,key:true},
        {name:'PROJECT_NAME',index:'PROJECT_NAME', align:'center',search:false,hidden: true},
        {name:'EMP_NAME',index:'EMP_NAME', sortable:true,summaryType:'count',summaryTpl : 'Total ({0}) Resource Hours' },
        <?php for($i=1;$i<=count($cal_arr);$i++) {?>
        {name:'<?php echo $i;?>',index:'<?php echo $i;?>',search:false,align:"center",sortable:false ,width:80 },
        <?php } ?>
    ],
    pager: "#page",
        multiselect: true,
    shrinkToFit :true,
    autowidth: true,
    viewrecords: true,
    grouping: true, 
    groupingView : { groupField : ['PROJECT_NAME'], 
                    groupColumnShow : [false], 
                    groupText : ['<b>{0}</b>'],
                    groupCollapse : false, 
                    groupOrder: ['asc'], 
                    groupSummary : [true], 
                    showSummaryOnHide: true,
                    groupDataSorted : true },
    sortname: 'EMP_NAME',
    caption: "Programatically block selection of some grid row',
    gridComplete: function () {
                    var recs = $("#grid").getGridParam("records");
                    $( ".mycontent" ).remove();
                    if (recs == 0 || recs == null) {
                        $('#grid').after("<div class='mycontent' style='color:red;text-align:center'>No Record Found</div>");
                        $("#btn_submit").hide();
                    }
            },


        loadComplete: function () {
            $("#cb_grid").click(); 
        },

            rowattr: function (item) {
                    if (parseInt(item.ID) == 1) {
                        return {"class": "ui-state-disabled ui-jqgrid-disablePointerEvents"};
                    }
            },

            //prevent selection of disabled rows
            beforeSelectRow: function (rowid, e) {
                if ($(e.target).closest("tr.jqgrow").hasClass("ui-state-disabled")) {
                    return false;   // not allow select the row
                }
                return true;    // allow select the row
            }

})

Above code does this

Required is

Using jqGrid with multiselect:true how to set each row checked by default on page load ? jQgrid Version - 4.6

If you use jqGrid 4.6 with datatype: "json" and no loadonce: true option then you have not so much possibilities. You have to enumerate all multiselect checkboxes of the grid and select there. So you can do

$("#cb_grid").click(); // "grid" is the grid id

inside of loadComplete callback for example. If you would think about all cases you will probably add more additional criteria, because loadComplete will be called on sorting, paging and so on.

UPDATED: You code have $('.cbox').attr('checked', true); line inside of rowattr. In the way you don't change the checkbox of the row, which is not yet exist. Instead of that you set checked attribute with wrong value true instead of "checked" on the checkbox of the column header. You should remove the line to be able to use the code which I suggested you:

loadComplete: function () {
    $("#cb_" + this.id).click();
},
rowattr: function (item, rd, rowid) {
    //$('.cbox').attr('checked', true);
    if (parseInt(rowid) === 10) {
        return {"class": "ui-state-disabled ui-jqgrid-disablePointerEvents"};
    }
},
beforeSelectRow: function (rowid, e) {
    if ($(e.target).closest("tr.jqgrow").hasClass("ui-state-disabled")) {
        return false;   // not allow select the row
    }
    return true;    // allow select the row
}

see the demo: http://jsfiddle.net/OlegKi/aagxejj5/4/