Örneğin;

<html>

<head>
<meta http-equiv="Content-Type" content="text/html; charset=windows-1254">
<title>Yeni Sayfa 1</title>
</head>

<body>

<input type="button" value="Yükle" onclick="jQueryYukle()">

<script>
function jQueryYukle(){
script1=document.createElement('script');
script1.src = 'https://ajax.googleapis.com/ajax/libs/jquery/1.7.1/jquery.min.js';
script1.type = 'text/javascript';
script1.onload=function(){alert("jQuery.min.js yüklendi!")}
document.getElementsByTagName("head")[0].appendChild(script1)

script2=document.createElement('script');
script2.src = 'assets/js/jquery-ui.js';
script2.type = 'text/javascript';
script2.onload=function(){alert("jQuery.ui.js yüklendi!")}
document.getElementsByTagName("head")[0].appendChild(script2)
}

</script>

</body></html>