is true, is not accepting javascript also. we have CMS pro that i used in one of our website group that have this option, allow users to add javascripts/php in thier code, is multi-languages support, built-in in compares packages, built-in whois search, built-in sliders, built-in domains extensions page, built-in contact page, built-in menus and nav bars menu, footer links, Seo-friendly and mush more wonderful and fantastic  features, we have not yet released for public, but we are in the way to release it.
 
	a dirty way to achieve your goal now is : 
 
	1 - create custom plugin that will show what you want.  
	2 - create a js file that has a ajax request to that plugin controller 
	3 - in the cms put the line to the js file. 
 
<script type="text/javascript" src="https://xxxxxx.com/plugins/your_plugin/views/default/js/your_js_file.js"></script>	
	we are using the same method in blesta-addons to list the latest products, you can check html source code to understand well . 
 
	our js file has this content
 
	fetch_latest_items();
	
	function fetch_latest_items() {
		$(this).blestaRequest("GET", "/plugin/store/main/latest_products/", null, function(data) {
			if (data)
				$(".portfolio-slider").html(data);
		},
		null,
		{dataType:"json"});
	}