I’m using something like this and it works well:
<?php
global $post;
if ( is_page( 'portfolio' ) ) {
echo '<script src="http://www.google.com/jsapi" type="text/javascript" charset="utf-8"></script>
<script type="text/javascript">
google.load("jquery", "1");
</script>
<script type="text/javascript" src="', bloginfo('template_directory'),'/js/masonry.js"></script>';
} elseif( get_post_type() == 'property' ) {
echo '<script type="text/javascript" src="', bloginfo('template_directory'),'/js/gallery.js"></script>';
} else {
}
?>