Update index.html

Typo corrected.

index.html

@@ -250,7 +250,7 @@
 						</select>
 					</td>
 					<td>
-						For long option lists the <code>maxheight</code> option can be set.
+						For long option lists the <code>maxHeight</code> option can be set.
 					</td>
 				</tr>
 				<tr>