public class ClientSidePage : System.Web.UI.Page
	{
		#region Methods for Prompting the User to Save Before Leaving the Page
		protected void MonitorChanges(WebControl wc)
		{
			if (wc == null) return;

			if (wc is CheckBoxList || wc is RadioButtonList)
				for (int i = 0; i < ((ListControl) wc).Items.Count; i++)
				{
					Page.RegisterArrayDeclaration("monitorChangesIDs", "\"" + string.Concat(wc.ClientID, "_", i.ToString()) + "\"");
					Page.RegisterArrayDeclaration("monitorChangesValues", "null");
				}
			else
			{
				Page.RegisterArrayDeclaration("monitorChangesIDs", string.Concat("\"", wc.ClientID, "\""));
				Page.RegisterArrayDeclaration("monitorChangesValues", "null");
			}			

			AssignMonitorChangeValuesOnPageLoad();
		}

		protected void AssignMonitorChangeValuesOnPageLoad()
		{
			if (!Page.IsStartupScriptRegistered("monitorChangesAssignment"))
			{
				Page.RegisterStartupScript("monitorChangesAssignment",
					@"<script language=""JavaScript"">
						assignInitialValuesForMonitorChanges();
					  </script>");

				Page.RegisterClientScriptBlock("monitorChangesAssignmentFunction",
					@"<script language=""JavaScript"">
						function assignInitialValuesForMonitorChanges() {
						    for (var i = 0; i < monitorChangesIDs.length; i++) {
						      var elem = document.getElementById(monitorChangesIDs[i]);
						      if (elem) if (elem.type == 'checkbox' || elem.type == 'radio') 
						          monitorChangesValues[i] = elem.checked;
						      else monitorChangesValues[i] = elem.value;
						    }
						 }
               
						var needToConfirm = true;
						window.onbeforeunload = confirmClose;
						
						function confirmClose() {
							if (!needToConfirm) return;
               
							for (var i = 0; i < monitorChangesValues.length; i++) {
								var elem = document.getElementById(monitorChangesIDs[i]);
								if (elem) if (((elem.type == 'checkbox' || elem.type == 'radio') && elem.checked != monitorChangesValues[i]) || (elem.type != 'checkbox' && elem.type != 'radio' && elem.value != monitorChangesValues[i])) { needToConfirm = false; setTimeout('resetFlag()', 750); return ""You have modified the data entry fields since last savings. If you leave this page, any changes will be lost. To save these changes, click Cancel to return to the page, and then Save the data.""; }
							}
						}
               
						function resetFlag() { needToConfirm = true; }
					</script>");
			}
		}

		protected void BypassModifiedMethod(WebControl wc)
		{
			wc.Attributes["onclick"] = string.Concat("javascript:", GetBypassModifiedMethodScript());
		}

		protected string GetBypassModifiedMethodScript()
		{
			return "needToConfirm = false;";
		}
		#endregion
	}