Add how-to about RadEditor content and back button

Author: Iankodj

controls/editor/how-to/preserve-content-on-back-button.md

@@ -0,0 +1,66 @@
+---
+title: Preserve the Content in RadEditor when Using Back Button
+page_title:  Preserve the Content in RadEditor when Using Back Button | RadEditor for ASP.NET AJAX Documentation
+description:  You can learn here possible solutions to preserve content when user has navigated to a page with RadEditor by using the browser's back button.
+slug: editor/how-to/preserve-content-on-back-button
+tags: back, history, forward, previous, browser, content, preserve, hidden, textarea, form
+published: True
+position: 11
+---
+
+# Preserve the Content in RadEditor when Using Back Button
+
+**RadEditor UI for ASP.NET AJAX** looses its content when user navigates out of the page and comes back by using the **Back** button of the browser. Browsers automatically preserve the content in such scenario only for form elements like `<textarea>`, `<input/>` and so on. **RadEditor**, however, is an editable DOM element that the browser does not consider as a form element field so to preserve its contents automatically. 
+
+Possible solutions: 
+
+* For **Chrome** and **Firefox**: You can use the `window.onbeforeunload` event in order to detect that user navigates out of the page and save the content of **RadEditor** in its own hidden `<textarea>`.
+
+	>caption Example 1: Solution with `window.onbeforeunload` event.
+
+
+		<telerik:RadEditor runat="server" ID="RadEditor" RenderMode="Lightweight"></telerik:RadEditor>
+
+		<a href="http://www.telerik.com/">Navigate to www.telerik.com</a>
+
+		<script>
+			window.onbeforeunload = function (ev) {
+				$find("<%= RadEditor.ClientID %>").saveContent();
+			};
+		</script>
+
+
+* For all browsers: IE cannot preserve the content during `window.onbeforeunload` and you can either save the content in the `<textarea>` while text is being typed in, or by using a `setTimeout` to not affect the performance of your page.
+
+	>caption Example 2: Solution with `onkeyup` event.
+
+
+		<telerik:RadEditor runat="server" ID="RadEditor" RenderMode="Lightweight" OnClientLoad="OnClientLoad"></telerik:RadEditor>
+
+		<a href="http://www.telerik.com/">Navigate to www.telerik.com</a>
+
+		<script>
+			function OnClientLoad(editor, args) {
+				editor.attachEventHandler("onkeyup", function (e) {
+					editor.saveContent();
+				});
+			}
+		</script>
+
+
+	>caption Example 3: Solution with `setInterval` approach.
+
+
+		<telerik:RadEditor runat="server" ID="RadEditor" RenderMode="Lightweight" OnClientLoad="OnClientLoad"></telerik:RadEditor>
+
+		<a href="http://www.telerik.com/">Navigate to www.telerik.com</a>
+
+		<script>
+			function OnClientLoad(editor, args) {
+				setInterval(function () {
+					editor.saveContent();
+				}, 5000);
+			}
+		</script>
+
+