C#

if (Regex.IsMatch(allRead, regMatch))//If the match is found in allRead

if (Regex.IsMatch(allRead, regMatch, RegexOptions.Singleline))//If the match is found in allRead

string fName = @"data.txt";//path to text file
           StreamReader testTxt = new StreamReader(fName);
           string allRead = testTxt.ReadToEnd();//Reads the whole text file to the end
           testTxt.Close(); //Closes the text file after it is fully read.
           string regMatch = @"(?<=\<div class=""middleadimggold""\>).*?(?=\</div\>)"; //string to search for inside of text file. It is case sensitive.
           if (Regex.IsMatch(allRead, regMatch))//If the match is found in allRead
           {
               Console.WriteLine("found\n");

           }
           else
           {
               Console.WriteLine("not found\n");
           }

<div class="middleadimggold">

		 

	 <a  class="asdf" href="http://www.asdf">
		 asdf</a>
   <p>
		 asdf</p>
		<p>asdf</p><p>asdf</p>
			  	 
			 <p><span class="blue">asdf</span>
			 &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<a class="de" href="http://www.4asdf"><span class="a">(See on map)</span></a></p>
		   
		<p><span class="blue">asdf</span></p>
		
		
	
		 <span class="xx">


asdf
  </span>
	
  </div>