the flavor or saliency you found there looks somewhat “low level”, but if it works, great!
here’s some more that might not be available. this is the stuff I remembered. it’s a bit more fuzzy.
https://docs.opencv.org/master/d8/d65/group__saliency.html
as I understand it, opencv.js has a “whitelist” of modules that translate correctly, as verified by humans. if you think it’s worth the bother, you could investigate and see if any as yet unavailable modules translate correctly as they are, or with any changes you think are necessary.