If you have a Google account, you can save this code to your Google Drive.
Google will ask you to confirm Google Drive access.
Save file as:
If you have saved a file to Google Drive, you can open it here:
Click the "Try it" button to make sure that the DIV element's height never becomes less than 400 pixels:
This DIV element does not have a pre-defined height.
The height of this DIV element depends on its content.
But if you click the "Try it" button, yo will make sure that this DIV element does not become less than 400 pixels in height.