Code for querying the page keyword density implemented by JS

I have been searching for keyword density query tools online for a long time. I still haven't found a proper keyword density query tool. Why? Because my website is UTF-8 encoded, most of the content provided on the Internet is gb2312. Continue to search for the keyword density query tool and find one, but instead of entering the URL, you need CodeCopied. Although such a keyword density query tool is not very useful, I did not find a better keyword density query tool at the moment. If you find it, contact me. Requirement: as long as you find keyword density query tools support UTF-8 encoding on it.