How to Remove All Options from a Dropdown Select Box with JavaScript
To remove all options from a dropdown select box with JavaScript, simply set the length property of the dropdown box to 0. For instance, if a dropdown select box is defined as follows:
<select name='Dropdown' id='Dropdown'>
<option value='1'>1</option>
<option value='2'>2</option>
</select>
Use this JavaScript to remove all the options in the dropdown select box.
document.getElementById('Dropdown').length = 0;