How can I Call Javascript method from C# Webmethod?

 function RunCode()
var FileName="anything";
 $.ajax({
        type: "POST",
        url: "Default.aspx/SetFileName",
        contentType: "application/json;charset=utf-8",
        data: "{'FileName':'" + FileName + "'}",
        dataType: "json",
        success: function (data) {

          Checking();

        },
        error: function (result) {
            //alert("Error login");

        }
    });
}

 function Checking() {
            //Some Codes to display images
            }

[WebMethod]
    public static string SetFileName(string FileName)
    {
        //Here I want to call JavaScript Method
    }