jQuery Grid Plugin - jqGrid

i set up colModel to one of the field to this value editrules:{required:true}

When I edit row, and i don't put any value, i see error modal box, and it say "Field is required", but the close button name is "undefined"

Is it posiible to change name to "Close" to all error modal box in jquery grid.

This is my colModel to one of the field:

{name:'state_name', index:'state_name', width:200, editable:true, edittype:'select', editoptions: { dataUrl: 'ajax_state.php' }, editrules:{required:true}, resizable: false},