Insert text between html tag using regex

Question

I want to insert &nbsp between empty paragraph tags.

Input:

1. <div><p></p></div>
2. <div><p style="margin: 0 0 0 0"></p></div>

Expected output:

1. <div><p>&nbsp;</p></div>
2. <div><p style="margin: 0 0 0 0">&nbsp;</p></div>

I tried to use look behind and forward but apparently I can't use quantifier here: (?<=< p[^>]*>)(?=<\/p>)

Any ideas? My available tools are regex and c#

Answer 1

You may be overthinking. I think all you need is to simply replace ></p> with >&nbsp;</p>, isn't it?

yourString = yourString.Replace("></p>", ">&nbsp;</p>");

EDIT

If you must use RegEx, then you do like this:

yourString = Regex.Replace(yourString, "(<p[^>]*>)(</p>)", "$1&nbsp;$2", RegexOptions.IgnoreCase);

Answer 2

Get all paragraphs tag and check their inner text if empty.

If its empty do something like getElementsByTagName('p')[0].innerHTML= '&nbsp';

Answer 3

(?<=>)(\s*)(?=<\/p>)