About .dojoxGridMasterHeader { display:none; }

http://stackoverflow.com/questions/11015641/about-dojoxgridmasterheader-displaynone

HTML

<link rel="stylesheet" href="http://ajax.googleapis.com/ajax/libs/dojo/1.7.1/dijit/themes/claro/claro.css">
<link rel="stylesheet" href="http://ajax.googleapis.com/ajax/libs/dojo/1.7.2/dojox/grid/resources/claroGrid.css">
<link rel="stylesheet" href="http://ajax.googleapis.com/ajax/libs/dojo/1.7.2/dojox/grid/resources/Grid.css">
<style>
   #gridDiv1 .dojoxGridHeader {
      display: none !important;
    }
    
    #gridDiv1 .dojoxGridCell {
       border-width: 1px 0 !important;           
    }
   
</style>    

<div id="gridDiv"></div>

CSS

#grid {
    width: 43em;
    height: 20em;
}

JavaScript

dojo.require("dojox.grid.DataGrid");
dojo.require("dojo.data.ItemFileWriteStore");
dojo.require("dojox.grid._CheckBoxSelector");

dojo.ready(function(){
    /*set up data store*/
    var data = {
      identifier: 'id',
      items: []
    };
    var data_list = [
      { col1: "normal", col2: false, col3: 'But are not followed by two hexadecimal', col4: 29.91},
      { col1: "important", col2: false, col3: 'Because a % sign always indicates', col4: 9.33},
      { col1: "important", col2: false, col3: 'Signs can be selectively', col4: 19.34}
    ];
    var rows = 60;
    for(var i=0, l=data_list.length; i<rows; i++){
      data.items.push(dojo.mixin({ id: i+1 }, data_list[i%l]));
    }
    var store = new dojo.data.ItemFileWriteStore({data: data});

    /*set up layout*/
    var layout = [
        {type: "dojox.grid._CheckBoxSelector", width: '40px' }
     ,[

      {'name': 'Column 1', 'field': 'id', 'width': '100px'},
      {'name': 'Column 2', 'field': 'col2', 'width': '100px'},
      {'name': 'Column 3', 'field': 'col3', 'width': '200px'},
              {'name': 'Column 4', 'field': 'col4', 'width': '110px'}
    ]];

    /*create a new grid:*/
    var grid = new dojox.grid.DataGrid({
        id: 'grid',
        store: store,
        structure: layout,
        rowSelector: '20px'},
      document.createElement('div'));

    /*append the new grid to the div*/
    dojo.byId("gridDiv").appendChild(grid.domNode);

    /*Call startup() to render the grid*/
    grid.startup();
});