How rowspan works in table

by Mobeen Sarwar

HTML

<table id="table-example-1">
<thead>
   <tr>
   <th rowspan="2">Grade.</th>
   <th rowspan="2">Yield Point.</th>
   <th colspan="2">Ultimate tensile strength</th>
   <th rowspan="2">Per cent </th>
   <th rowspan="2">reduct. area.</th>
   </tr>
   <tr>
   <th>kg/mm</th>
   <th>lb/in</th>
   </tr>
</thead>
    
</table>

CSS

#table-example-1 { 
  border: solid thin; 
  border-collapse: collapse; 
}
#table-example-1 th{ 
  border: solid thin;
  padding: 0.5rem 2rem;
}

#table-example-1 th { 
  font-weight: normal; 
}

#table-example-1 th { 
  padding: 0.2em; 
  vertical-align: middle; 
  text-align: center; 
}