How to make JS Async and eliminate unnecessary JS?
you can use async_js for loading asynchronly.

and in hook_js_alter you can remove js files you don't want to have on the page.

you can also place the JS at the bottom of the page in your theme's html.tpl.php, by printing

&lt;?php print $scripts; ?&gt;

just before the &lt;/body&gt; tag.