Use client- script to get the data id for multiple selection

Use client- script to get the data id for multiple selection

After selecting data in multiple selections, I found that there was an array object called selectid, but it was not included in the packaged SDK. We were unable to obtain which data had been selected, resulting in no way to filter the corresponding data to populate the child form.
Or is there any way to get the data id for multiple selection? Thanks.