A method for adding new entries to the bottom of an index with AJAX in Movable Type. It requires jQuery.

pagination.js

$(document).ready(function() {
	var page = 1;
	$('.load-posts').click(function() {
		$('.article:last').after('<div id="ajax-loader">Loading Data</div>');
		page++;
		var contentUrl = '/cgi-bin/mt/mt-search.cgi?page=' + page;
		if ($(this).attr('id') == 'category-posts') { contentUrl += '&IncludeBlogs=1&limit=20&category=' + catId + '&archive_type=Category'; }
		if ($(this).attr('id') == 'index-posts') { contentUrl += '&IncludeBlogs=1,4&limit=20&archive_type=Index'; }
		$.get(contentUrl, function(data) {
			if (data != '') {
				$('.article:last').after(data);
				$('#ajax-loader').remove();
			} else {
				$('#load-posts').remove();
				$('#ajax-loader').remove();
			}
		});
		return false;
	});
});

search-results.mtml

<mt:Unless name="request.archive_type">
<!-- Normal search template code goes here -->
<mt:Else>
	<mt:SearchResults limit="20">
	<mt:Include module="Entry Summary">
	</mt:SearchResults>
</mt:Unless>