Add new rows to WebCombo in client-side javascript

Infragistics.WebUI.UltraWebGrid.UltraWebGrid comboGrid = (Infragistics.WebUI.UltraWebGrid.UltraWebGrid) this.WebCombo1.Controls[0];

Then allow add new and updates to the WebGrid

if(comboGrid != null)
{
comboGrid.DisplayLayout.AllowAddNewDefault = Infragistics.WebUI.UltraWebGrid.AllowAddNew.Yes;
comboGrid.DisplayLayout.AllowUpdateDefault = Infragistics.WebUI.UltraWebGrid.AllowUpdate.Yes;
}

Write javascript to call the igtbl_addNew method to add a new row to the grid inside of the combo:

function AddNewRow()
{
var cbo = igcmbo_getComboById('WebCombo1');
var row = igtbl_addNew(cbo.grid.Id, 0);
row.getCell(0).setValue(11);
row.getCell(1).setValue("Name11");
row.getCell(2).setValue(new Date());
}