HTML

rowspan

<table> 
  <tr>
    <td rowspan= "2"> lorem </td>
    <td> Ipsum </td>
    <td> lorem </td>
  </tr>    
  
  <tr>
    <td> lorem </td>
    <td> ipsum </td>
  </tr>    
<!-- Here we have 2 rows and 3 columns, but we have created 3 in the first,
and 2 in the second. In this case because we used rowspan, the first cell
in the first row will take also a space in the second row so it'll be merged.-->

header with rowspan

<table>
  <thead>
    <tr>
      <th rowspan="2">No.</th>
      <th rowspan="2">Creation Date</th>
      <th rowspan="2">Week Day</th> 
      <th rowspan="2">Log Type</th>
      <th colspan="2" style="text-align: center">Time</th>
      <th rowspan="2">action</th>
    </tr>
    <tr>
      <th>IN/START</th>
      <th>OUT/STOP</th>
    </tr>
  </thead>
</table>

rowspan 1.5 html

<table border="2">
			<tr>
				<th rowspan="3">Day</th>
				<th colspan="3">Seminar</th>
			</tr>
			<tr>
				<th colspan="2">Schedule</th>
				<th rowspan="2">Topic</th>
			</tr>
			<tr><th>Begin</th><th>End</th></tr>
			<tr>
				<td rowspan="2">Monday</td>
				<td rowspan="2">8:00 a.m.</td>
				<td rowspan="2">5:00 p.m.</td>
				<td>Introduction to XML</td>
			</tr>
			<tr><td>Validity:DTD and Relax NG</td></tr>
			<tr>
				<td rowspan="3">Tuesday</td>
				<td>8:00 a.m.</td>
				<td>11:00 a.m.</td>
				<td rowspan="1.5">XPath</td>
			</tr>
			<tr>
				<td>11 a.m.</td>
				<td>2:00 p.m.</td>
			</tr>
			<tr>
				<td>2:00 p.m.</td>
				<td>5:00 p.m.</td>
				<td rowspan="1.5">XSL Transformations</td>
			</tr>
		</table>
 Run code snippet

rowspan in css style

rowspan is not something that we can do in css. It is a particular attribute for table. There are some other things also like cellspacing, cellpadding, Colspan which we cannot do in css.