Do something visible on the right side after user input

Question

Now the user enters a zip code on the left side there. After input, I want the delivery method to be visible on the right side. If no zip code is entered, the delivery method must remain invisible.

 
The first user with html, css and C #, so any information would be greatly appreciated. Thanks!

Answer 1

According to the requirement of only HTML / CSS, you can use the direct selector +to conditionally show / hide elements depending on the validity of the input.

input:invalid + select { display: none; }

<input type="text" pattern="\d{5}" placeholder="ZIP code" required>
<select>
  <option>one</option>
  <option>two</option>
</select>

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