When i add the "ItemSend" Event handler in my add-ins manifest.xml thrown error while installing the add-ins

In outlook add-ins try to add the ItemSend Event handling trigger in the manifest file ,but when i try to install manifest.xml not installing some error thrown

How to add the item send Event handler on my outlook add-ins

How to trigger this when click the save button , how to trigger the event on my commands.js file

Note : my add-ins developed by using javascript

Any thought about that please share me

Thanks in advance

First of all, make sure the right requirement set is specified in the manifest file. You must specify at least the 1.8 set for the ItemSend event because the on-send feature was officially released in requirement set 1.8. Read more about requirement sets in the Requirements for running Office Add-ins article.

In the manifest file, you typically need to include the function file and function name that should be called on the ItemSend event. The operation runs synchronously.

<Hosts>
    <Host xsi:type="MailHost">
        <DesktopFormFactor>
            <!-- The functionfile and function name to call on message send.  -->
            <!-- In this case, the function validateBody will be called within the JavaScript code referenced in residUILessFunctionFileUrl. -->
            <FunctionFile resid="residUILessFunctionFileUrl" />
            <ExtensionPoint xsi:type="Events">
                <Event Type="ItemSend" FunctionExecution="synchronous" FunctionName="validateBody" />
            </ExtensionPoint>
        </DesktopFormFactor>
    </Host>
</Hosts>

The on-send API requires VersionOverrides v1_1. The following XML markup shows you how to add the VersionOverrides node in your manifest.

 <VersionOverrides xmlns="http://schemas.microsoft.com/office/mailappversionoverrides" xsi:type="VersionOverridesV1_0">
     <!-- On-send requires VersionOverridesV1_1 -->
     <VersionOverrides xmlns="http://schemas.microsoft.com/office/mailappversionoverrides/1.1" xsi:type="VersionOverridesV1_1">
         ...
     </VersionOverrides>
</VersionOverrides>

Read more about that in the On-send feature for Outlook add-ins article.

You may also find the Outlook-Add-in-On-Send sample add-in on GitHub.