I researched a lot about this problem. Please see my attachment. I added this script to get out of this error form google page speed insights tool. But still its showing that file. How to solve it?

<script type="text/javascript">
function downloadJSAtOnload() {
var element = document.createElement("script";
element.src = "wp-content/plugins/LayerSlider/static/js/greensock.js?ver=1.11.8";
document.body.appendChild(element);
}
if (window.addEventListener)
window.addEventListener("load", downloadJSAtOnload, false);
else if (window.attachEvent)
window.attachEvent("onload", downloadJSAtOnload);
else window.onload = downloadJSAtOnload;
</script>

Can anyone help?

i see that your site is on wordpress, if you want to remove the file. login via your cpanel, locate the current theme folder , navigate to functions.php file.

search for the "greenstock" and and comment that line out with "//".

that should remove the code block enqueuing that file.

hope you understand.

Have you tried generating the css for the sbove the fold content with services like the one from sitelocity ?