Merge branch 'master' of https://github.com/SharePoint/sp-dev-docs

Author: davidchesnut

docs/general-development/modern-pages-maintenance-mode.md

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+---
+title: Maintenance mode for client-side web parts
+ms.date: 12/18/2017
+ms.prod: sharepoint
+ms.assetid: 3ebd2a11-8291-4228-add0-9e0cd899dd3c
+---
+
+# Maintenance mode for client-side web parts
+
+_**Applies to:** Office 365_
+
+When working with client-side web parts, you can load them in maintenance mode. The maintenance mode can be helpful when trying to debug issues related to web parts placed on the page.
+
+## Switch to maintenance mode
+
+> [!NOTE]
+> In order to load a page in the maintenance mode, you have to have edit permissions for that specific page.
+
+To switch to the maintenance mode, navigate to the page and in the URL append `?maintenancemode=true`, for example:
+
+```text
+https://contoso.sharepoint.com/sites/team?maintenancemode=true
+```
+
+To leave the maintenance mode, remove `?maintenancemode=true` from the URL and reload the page.
+
+## Available information
+
+The maintenance mode shows various information about each web part on the page.
+
+### Web part summary
+
+When in maintenance mode, for each web part you will see the following summary information:
+
+![Web part summary information displayed in maintenance mode](../images/maintenance-mode-summary.png)
+
+Property|Description
+--------|-----------
+Alias|Web part alias
+Id|The unique ID of the web part
+InstanceId|The ID of a specific instance of a web part (that is, if you have two more of the same web parts on a page, they will each have the same web part ID, but a different instance ID.
+IsInternal|Indicates whether the web part was made by Microsoft or a third party. If `true`, it is made by Microsoft. If `false`, it is made by a third party.
+Version|The version number of the web part.
+Environment|Enumeration indicating the environment on which the web part is running. Possible values: `1` - Local Workbench, `2` - SharePoint
+UserAgent|A string that contains information about the device and software in use (such as browser type and version).
+
+### Web part manifest
+
+To get more information about the web part, switch to the **Manifest** tab.
+
+![Web part manifest information displayed in maintenance mode](../images/maintenance-mode-manifest.png)
+
+By exploring the manifest information, you can learn details such as:
+
+- where the web part bundle is hosted
+- which external scripts is the web part loading and from where
+- what version of the SharePoint Framework has the web part been built on
+- which components of the SharePoint Framework does the web part use
+
+This information can be invaluable when trying to find a reason why the particular web part is malfunctioning.
+
+### Web part data
+
+Another piece of information available in the maintenance mode, is web part data.
+
+![Web part data information displayed in maintenance mode](../images/maintenance-mode-data.png)
+
+Using the information from the **Data** tab, you can see the configuration for each web part. This is helpful when trying to reproduce errors reported by users which could be caused by a specific web part configuration.
+
+If the web part [integrates its properties with SharePoint](../spfx/web-parts/guidance/integrate-web-part-properties-with-sharepoint.md), the data section shows the types and values that are passed to SharePoint for further processing.
+
+## Considerations
+
+- the maintenance mode works for client-side web parts placed on both modern and classic SharePoint pages. See the [Open and use the web part maintenance page](https://support.office.com/en-us/article/Open-and-use-the-web-part-maintenance-page-eff9ce22-d04a-44dd-ae83-ac29a5e396c2#PickTab=2016,_2013) support article, to get more information about opening classic web parts in maintenance view
+- to open page in maintenance mode, you have to have edit permissions for that page
+- when in maintenance mode, web part code is not being executed and you cannot edit web part properties
+- in maintenance mode, you can delete or move web parts on the page
+- the maintenance mode shows only information about web parts. You cannot use it to show information about SharePoint Framework extensions that are executed on the page
+- switching to maintenance mode only disables executing web part code. Any SharePoint Framework extensions registered on the page will still execute
+
+## See also
+
+- [Open and use the web part maintenance page](https://support.office.com/en-us/article/Open-and-use-the-web-part-maintenance-page-eff9ce22-d04a-44dd-ae83-ac29a5e396c2)