Display (Show) loading Image when binding Kendo UI DropDownList in ASP.Net MVC

hi;

I am filling the kendo dropdown using ajax method and sometimes its getting the value too late, I want to show a loading icon when try to get value.

@(Html.Kendo().DropDownListFor(x => x.CUSTOMER)
              .Name("CUSTOMER")
              .DataTextField("Text")
              .DataValueField("Value")
              .MinLength(2)
              .Filter("contains")                                               
              .Events(x => x.Open("FillData"))
              .Animation(true)
              .IgnoreCase(true)
              .HtmlAttributes(new { style = "width:160px;" })                                              
)

function FillData() {
    var clname = $('#CUSTOMER').data("kendoDropDownList");
    $.ajax({
        url: '/Operations/GetCustomer',
        type: "Post",
        success: function (model) {
            clname.setDataSource(model.CUSTOMER);
        },
        error: function (model) {
            console.log(model);
        } 
    }); 
};