Since you can't use negative lookbehinds in JavaScript, how would you achieve the same regex match without one, using a lookahead or some other JavaScript supported method?

`(?<!<\/strong>\n\s{4}|<\/strong>&nbsp;\n\s{4})<br>`

I'm trying to find all `<br>` tags that are not preceded by `</strong>` and `</strong>&nbsp;` followed by a line break and a series of whitespace chars.

[Here's my code](https://regex101.com/r/ZactBT/1) and some sample text for testing. I got it working in pcre with the lookbehind but I can't figure out how to make it work in JavaScript.

I've tried the other examples here but I was unable to figure out how to implement those solutions according to my needs.

**UPDATE** Javascript lookbehinds are [coming in ES2018](http://2ality.com/2017/05/regexp-lookbehind-assertions.html)!