JSOM : Unable to update Custom list item

Question

I have Read User having read Permission.

I'm trying to update the list item using JSOM. But I get below error

"Access denied. You do not have permission to perform this action or access this resource."

    try {
    var list = clientContext.get_site().get_rootWeb().get_lists().getByTitle("ListName");

    var reportListItem = list.getItemById(CommentId);
    reportListItem.set_item('Reported_Flag', '1');
    reportListItem.set_item('Report_Comment', commentText);
    reportListItem.update();

    clientContext.executeQueryAsync(function () {
        $('#reportModal textarea').val("");
        $("#reportModal").modal("hide");



    }, function (xhr, textStatus, errorThrown) {
        ULS.enable = true
        ULSOnError(" - Unable to get report the comment in Comments list - " + textStatus + errorThrown, location.href, 0)
    });
}
catch (error) {
    console.log("  - " + error.message);
    ULS.enable = true;
    ULSOnError(" - " + error.message, location.href, 0);
}

Answer 1

Using JSOM you have the exact same permissions as the current user (no more and no less), so if the current user only have read permission, then you can't update.

Answer 2

You cannot update the list items using JSOM with only Read permission.

In order to add/update/delete list items, you should at least have Contribute permissions.

For more understanding, check below article:

Understanding permission levels in SharePoint.