幸运的是，网页无法满足您的需求。它不能做的一件事是写入您的存储（想象一个恶意网站，用一些病毒填充本地磁盘），因此您无法在网页内写入JavaScript文件......

Fortunately a web page can not do whatever it wants with your computer. One of the things it cannot do is writing to your storage (imagine a malicious website that fill you local disk with some viruses), so you can not write files from JavaScript inside a web page...