re = /<div.+?>(.+)?<\/div>/i
str = '<h3>Programma en uitslagen</h3>
<table width="100%">
<tr>
<th>ronde</th>
<th>dag</th>
<th>datum</th>
<th></th>
<th>thuis</th>
<th>uit</th>
<th> </th>
<th colspan="1"> </th>
<th colspan="2">uitslag</th>
<th>ct</th>
<th>cu</th>
<th> </th>
</tr>
<tr>
<td class="getal">1</td>
<td>Ma.</td>
<td>22-08-2016 19:30</td>
<td>
<div title="Add to Calendar" class="addthisevent">
<span class="start">22/08/2016 19:30:00</span>
<span class="end">22/08/2016 22:30:00</span>
<span class="timezone">Europe/Amsterdam</span>
<span class="title">Kamperduin 1 vs Kamperduin 2</span>
<span class="description">Biljartwedstrijd 3Bnd B1 - Ronde 1</span>
<span class="location"></span>
<span class="organizer">KNBB</span>
<span class="organizer_email"></span>
<span class="all_day_event">false</span>
<span class="date_format">DD/MM/YYYY</span>
<span class="alarm_reminder">60</span>
</div>
</td>
<td><a href="http://www.biljartpoint.nl/index.php?page=teamdetail&team_id=29629&compid=2470&poule=A&district=57">Kamperduin 1</a></td>
<td><a href="http://www.biljartpoint.nl/index.php?page=teamdetail&team_id=29627&compid=2470&poule=A&district=57">Kamperduin 2</a></td>
<td></td>
<td> </td>
<td></td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
</tr>'
subst = ' gdgf'
result = str.sub(re, subst)
# Print the result of the substitution
puts result
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for Ruby, please visit: http://ruby-doc.org/core-2.2.0/Regexp.html