I have a webscript which would read all selected items.
Which query I should use?
ASPECT:"cm:checkedOut"
not running.
Alfresco - How to get all checked out documents? - Stack Overflow
Ok, now I understand.
When you configure a new action in that menu, the javascript action you define will receive the selected nodes automatically.
You can see how it is done by looking at the Share's source code.
The action configuration: share/share-documentlibrary-config.xml at master · Alfresco/share · GitHub
And the javascript code executed when the user clicks on the action: share/actions.js at master · Alfresco/share · GitHub
Follow that model and you will get what you need.
What have you tried exactly?
Can you share some code to give us an idea on what you are doing?
Without any context, it will be hard to help you.
I have a new action for selected items.
<action type="action-link" id="idOfJavascript" permission="Write" label="someLabel" />
And now I need to read all selected items in this page. The question is how Alfresco read this files?