With the Document Object Model (DOM), you can create almost everything in HTML dynamically with Javascript. The fundamental reason is that the <script> tag is no different from other elements in the page: they can all be referenced through DOM, they can be moved, deleted, or even created in the document. Using the standard DOM method, it is very easy to create a New Year's <script> element:
The code copy is as follows:
<script type="text/javascript">
var script=document.createElement("script");
script.type="text/javascript";
script.src="file1.js";
document.getElementByTagName("head")[0].appendChild(script);
</script>
This newly created <script> element loads the file1.js file. The file starts downloading when the element is added to the page. The key point of this technique is that whenever the download is started, the download and execution of the file will not block other processes on the page. You can even put the code in the <head> area of the page without affecting other parts of the page.