$( function() {
	$( "#go-button" )
		.mouseover( function() { $( this ).css( "background-position", "center right" ) } )
		.mouseout( function() { $( this ).css( "background-position", "top right" ) } )
		.mousedown( function() { $( this ).css( "background-position", "bottom right" ) } )
		.mouseup( function() { $( this ).mouseover() } )
		.click( function() { location.href = "refer_friend.xml"; } );
} );