move the contents of a div to another div

move the contents of a div to another div

I have a div structure such that:

<div id="MainDiv">


<div id="fromDiv">
<div id="NewContents">
</div>
</div>
<div id="toDiv">
<div id="ExisitngContents">
</div>
</div>

</div>

Now i want the jquery to move(append) the NewContents from fromDiv to toDiv such that the new structure will be


<div id="MainDiv">


<div id="fromDiv">
</div>

<div id="toDiv">
<div id="ExisitngContents">
</div>
<div id="NewContents">
</div>
</div>

</div>