How to find a line that has a non-closed tag and close it?

Question

PHP

I have a site where a person can write an "article", but it may be that he did not close the tag and then everything (not only the user's text, but also the site itself) will change.
For example, there is a line: Hello.
And because of this, the site can "fly".

Answer 1

Try to search with a regular expression
And in general how to understand unclosed?