I have an array in javascript:

```
var elements = [ // original hierarhical array to display
            {key:10, label:"Web Testing Dep.", open: true, children: [
                {key:20, label:"Elizabeth Taylor"},
                {key:30, label:"Managers",  children: [
                    {key:40, label:"John Williams"},
                    {key:50, label:"David Miller"}
                ]},
                {key:60, label:"Linda Brown"},
                {key:70, label:"George Lucas"}
            ]},
            {key:110, label:"Human Relations Dep.", open:true, children: [
                {key:80, label:"Kate Moss"},
                {key:90, label:"Dian Fossey"}
            ]}
        ];

```

If I want to add a whole new element I can use a `push()`. But I want to add a part of an element.
for exemple I want to add

```
var toAdd = {key:100, label:"Johny Dep"}

```

To the children of key 10 "web testing dep.". 
Is it also possible with a `push()`?