In your RegEx, try changing this:
"(.*)"
to this:
"([^<]*)"
So, instead of matching ANY character, you match any characters up to (but not including) the next less-than symbol.
You might also want to change this:
"</" + htmlTag + ">"
to this
"</ ?" + htmlTag + ">"
To allow for a space after the slash (you can ignore this second suggestion if you have full control over the HTML documents and know exactly how they were coded)
与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…