SharePoint JavaScript 更新用户和组字段

　　前言

　　最近，需要更新列表字段，字段的类型是用户和组，so写了这么一段代码

function updateUserField(){
    var ctx = new SP.ClientContext.get_current();
    var list = ctx.get_web().get_lists().getByTitle('My List');
    var item = list.getItemById(1);//Item Id

    var assignedToVal = new SP.FieldUserValue();
    assignedToVal.set_lookupId(12);//User Id in the site collection
    item.set_item("AssignedTo",assignedToVal);//AssignedTo is a column name
    item.update();

    ctx.executeQueryAsync(
        function() {
            console.log('Updated');
        },
        function(sender,args) {
            console.log('An error occurred:' + args.get_message());
        }
    );
}
ExecuteOrDelayUntilScriptLoaded(updateUserField, "sp.js");