When the checkbox checked I want to appear a select tag

In my template i'm writing a form. But there is a problem. I want to show a dropdown select menü if checkbox is checked. Otherwise it won't be visible. Here is my codes:

<label for="webcam">Webcam*</label>

    <input type="checkbox" name="webcam" value="checkbox">

     <select>
       <option value="1">1</option>
       <option value="2">1</option>
       <option value="3">1</option>
       <option value="4">1</option>
     </select>