Setting a max height on a table

NOTE this answer is now incorrect. I may get back to it at a later time.

As others have pointed out, you can't set the height of a table unless you set its display to block, but then you get a scrolling header. So what you're looking for is to set the height and display:block on the tbody alone:

<table style="border: 1px solid red">
    <thead>
        <tr>
            <td>Header stays put, no scrolling</td>
        </tr>
    </thead>
    <tbody style="display: block; border: 1px solid green; height: 30px; overflow-y: scroll">
        <tr>
            <td>cell 1/1</td>
            <td>cell 1/2</td>
        </tr>
        <tr>
            <td>cell 2/1</td>
            <td>cell 2/2</td>
        </tr>
        <tr>
            <td>cell 3/1</td>
            <td>cell 3/2</td>
        </tr>
    </tbody>
</table>

Here's the fiddle.

• Set display: block; for the table
• Set position: sticky; top: 0; for the header row

<table style="display: block; height: 100px; overflow: auto;">
  <thead>
    <tr>
      <td style="position: sticky; top: 0;">Header stays put</td>
      <td style="position: sticky; top: 0;">Layout aligned</td>
    </tr>
  </thead>
  <tbody>
    <tr>
      <td>foo1</td>
      <td>Header stays put</td>
    </tr>
    <tr>
      <td>foo2</td>
      <td>Header stays put</td>
    </tr>
  </tbody>
</table>

https://jsfiddle.net/0zxk18fp/

Tested on Chrome, Firefox, Safari, Edge

Add display:block; to the table's css. (in other words.. tell the table to act like a block element rather than a table.)

fiddle here

You can do this by using the following css.

.scroll-thead{
    width: 100%;
    display: inline-table;
}

.scroll-tbody-y
{
    display: block;
    overflow-y: scroll;
}

.table-body{
    height: /*fix height here*/;
}

Following is the HTML.

<table>
 <thead class="scroll-thead">
          <tr> 
           <th>Key</th>
           <th>Value</th>
          </tr> 
         </thead>
         <tbody class="scroll-tbody-y table-body">
          <tr> 
          <td>Blah</td> 
          <td>Blah</td> 
          </tr> 
</tbody>
</table>

JSFiddle