正则表达式查找所有关闭的html标签，所有均单独打开

Question

I have a javascript function performing filtering on strings. I currently have the filter stripping out all html tags.

return String(text).replace(/<[^>]+>/gm, '');

I've realized that I actually need to perform two operations: First, to replace all closing tags with <br> and then a second operation to remove all opening tags.

I'm not too familiar with regEx. How could I specify /<[^>]+>/gm to be only opening or closing?

Answer 1

You need to use double replace function.

> var str = "<h1>foo bar</h1>"
undefined
> str.replace(/<\w[^>]*>/, "").replace(/<\/[^>]+>/, "<br>")
'foo bar<br>'

OR

Use single replace function which uses a capturing group based regex.

> var str = "<h1>foo bar</h1>"
> str.replace(/<(\w+\b)[^>]*>([^<>]*)<\/\1>/, '$2<br>')
'foo bar<br>'

We must back-reference ( \\1 ) to the first capturing group instead of second because the 1st itself contain the tag-name.