RegisterClientScriptBlock is not working in ASCX page

Hi Team,

My script is not working which I have written on Radbutton click for a particular condition in ASCX code behind page.

My Script

  function confirmSubmit(confirmMsg) {
            debugger;
            function callbackFunctionPerformStartProcessValidation(arg) {
                if (arg) {
                    debugger;
                    var argument = "Start Process";$find("<%= RadAjaxManager.GetCurrent(Page).ClientID %>").ajaxRequest(argument);
                }
            }
            radconfirm(confirmMsg, callbackFunctionPerformStartProcessValidation, 300, 100, null, "Start Process Warning");
        }

Rad Button click

  string Tag = string.Empty;
                            string confirmMsg = string.Empty;
                            List<string> factTag = presenter.GetFactTagAssociated(projectId, DsId);
                            if (factTag.Count > 0)
                            {
                                confirmMsg += "The listed facts will be impacted.\n";
                               confirmMsg += "\n Do you want to continue?";
                            }
                                                     ScriptManager.RegisterClientScriptBlock
                            (this.Page,  this.GetType(), "confirmSubmit", "<script type='text/javascript'>confirmSubmit('" + confirmMsg + "')</" + "script>", false);
                                                     return;
                        }

After hitting the rad button, nothing is happening. It is not hitting the script too. Please let me know how to progress. It's really blocking me to progress.

Thanks in advance.

Rosalini