Question

the basic idea is to have three options

1. email #1 from database
2. email #2 from database
3. new email

When user would choose #3, a textbox would expand on bottom of dropdown so entering new email would be accessible.

Have you seen something like this anywhere? Any samples/techniques?

Answer 1

All this requires is having a form field whose initial properties are style="display:none", then showing it if the third option is chosen.

Here’s the poor man’s version:

<select onchange="displayEmail(this)">
   <!-- Put your items here -->
</select>
<input type="text" name="email" id="email" style="display: none;" />

JS:

function displayEmail(element) {
    if(element.selectedIndex==2) {
        document.getElementById('email').style.display = "";
    }
}