Now works. JSONP is ok, you can use it without your PHP.
<script type="text/javascript">
$( document ).ready(function() {
$.ajax({
url:'http://api.rottentomatoes.com/api/public/v1.0/lists/movies/upcoming.json?page_limit=16&page=1&country=us&apikey=k4uaze4937mw3hf82upstxqw',
type:'GET',
dataType:'jsonp',
success:function(data){
alert(data);
var title1 = data.movies[1].title;
alert(title1);
},
error: function(xhr, textStatus, errorThrown){
alert(xhr);
alert(textStatus);
alert(errorThrown);
}
});
});
</script>