problem on loading a div


when i try to load dhtmlxtabbar div (onchange of select button)… it loads multiple divs…

my code is…

function showGrid(str){ //alert(str)

if(str==‘’){

document.getElementById(‘tabbar’).style.display=‘none’;

}
else if(str!=‘’ ){
document.getElementById(‘tabbar’).style.display=‘block’;
}
tabbar = new dhtmlXTabBar(“tabbar”, “top”);
tabbar.setSkin(‘dhx_skyblue’);
tabbar.setImagePath(“dhtmlxSuite/dhtmlxTabbar/codebase/imgs/”);
tabbar.addTab(“a1”, “Customers Monthly Requirement”, “210px”);
tabbar.addTab(“a2”, “Dispatching Quantity”, “200px”);
tabbar.setTabActive(“a1”);
var mygrid = tabbar.cells(“a1”).attachGrid();
mygrid.setImagePath(“dhtmlxSuite/dhtmlxGrid/codebase/imgs/”);
mygrid.loadXML(“invoice_xml.php?Cust_Id=”+str);

var mygrid1 = tabbar.cells(“a2”).attachGrid();
mygrid1.setImagePath(“dhtmlxSuite/dhtmlxGrid/codebase/imgs/”);
mygrid1.loadXML(“dhtmlxSuite/dhtmlxTabbar/samples/common/grid.xml”);

how to load single div each time trigger onchange function…

Please explain the issue in detail. What did you mean ?