height

The height CSS property specifies the height of the content area of an element. The content area is inside the padding, border, and margin of the element.
 
The min-height and max-height properties override height.

Values

<length>
See <length> for possible units.
<percentage>
The <percentage> is calculated with respect to the height of the containing block. If the height of the containing block is not specified explicitly, the value computes to auto. A percentage height on the root element (e.g. <html>) is relative to the viewport.
auto
The browser will calculate and select a height for the specified element.

<!DOCTYPE html>
<!DOCTYPE html>
<html>
    <head>
        <style>
            table {
                height: 100%;
            }
            
            img {
                height: 200px;
            }
            
            form {
                height: auto;
            }
            
  /* make sure percentage height of body's children works as expected */
            body {
                margin: 0;
                height: 100%;
            }
        </style>
    </head>
    <body>
        <table>
            <tr>
                <td>
                    1
                </td>
                <td>
                    2
                </td>
            </tr>
        </table>
        <img src="preview.jpeg" />
        <form>
            <input type="button" name="first">
        </form>
        </html>