Example 1:

<script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.3/jquery.min.js"></script>
<div id="test"><a href="#" class="expand" onclick="onclick2();">Change 1</a></div>
<script type="text/javascript">
function onclick1() {
	$( '#test .expand' ).attr({
		onclick: 'onclick2();'
	});
	$( '#test .expand' ).html( 'Change 1' );
}

function onclick2() {
	$( '#test .expand' ).attr({
		onclick: 'onclick1();'
	});
	$( '#test .expand' ).html( 'Change 2' );
}
</script>


------------------------
Example 2:

<div id="test2"><a href="#" class="expand" onclick="onclick3();">Change 3</a></div>
<script type="text/javascript">
function onclick3() {
	$( '#test2 .expand' ).attr( 'onclick', 'onclick4();' ).html( 'Change 4' );
}

function onclick4() {
	$( '#test2 .expand' ).attr( 'onclick', 'onclick3();' ).html( 'Change 3' );
}
</script>