试例：
[Popid=25]观点[/Popid] 转成 <a href='javascript:ShowView(25)' style='text-decoration:underline;'>观点</a>
UBB转HTML:
string Cont = "[Popid=25]观点[/Popid]";
Regex rg=new Regex(@"\[Popid\=([0-9]+)\](.+)\[\/Popid\]",RegexOptions.IgnoreCase);
Cont = rg.Replace(Cont,@" <a href='javascript:ShowView($1)' style='text-decoration:underline;'>观点</a>");
HTML转UBB:
string Cont = "<a href='javascript:ShowView(25)' style='text-decoration:underline;'>观点</a>";
Regex rg=new Regex(@" \<a href=\'javascript:ShowView\(([0-9]+)\)\' style=\'text-decoration:underline;\'\>观点\<\/a\>");
Cont = rg.Replace(Cont.Trim(),@"[Popid=$1][/Popid]");