I used the following Tool Visual Ribbon Editor, and you will see screenshots for the button configuration.
Created the Button and called "Attendance", the next step is to create the Actions and the Enable Rules
in the actions I created a JavaScript function with the name "processrecords" a lot of imagination on the function name. Added to the library EventAttendee_Ribbon.js web resource file, and the most important part was the CRM Parameter
Cmd Parameters: SelectedControlSelectedItemIds (this will
pass the parameters for the function and then assign the Grid Selected ID’s)
Next the options for Enable the button when selecting 1 or more records from the subgrid.
Applies to: SelectedEntity
Maximum:
Minimun: 1
Save and Publish the button configuration, update the web resources for the JavaScript
Testing the Button and selecting a couple of records
Final Test Results and Validation.
The following is the Javescript code I used to update the values for the record. the code was using oData and JQuery to update the selected records.
in the same web resourse file I included the Jquery.js, also the SDZK.Rest.js and finally the code on the next image
Hope this help you in your projects.
Abe Saldana.