The main problem with regex removing HTML comments is that it can leave behind unintended content. For example, if you were to remove all the HTML comments from a document, you would likely end up with a document that is missing important information.
<!--This is a comment--> This is a comment
Removing HTML comments with Regex
There are a few ways to remove HTML comments with regex. One way is to use the /g flag on the regular expression engine in your text editor. This will match any character except newlines, which will cause the comment to be removed.
Another way is to use a character class. You can create a character class by using the [^s] flag, which will match any character that is not a space. Then, you can use the s escape sequence to match spaces, and the /g flag on the regular expression engine to remove comments.
Tools to learn Regex
There are many tools that can be used to learn regex in HTML. One popular tool is RegexBuddy, which can be found at http://www.regexbuddy.com/. Another tool is RegExr, which can be found at https://regexr.com/.