[html] HTML combo box with option to type an entry

Before datalist (see note below), you would supply an additional input element for people to type in their own option.

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<select name="example">
  <option value="A">A</option>
  <option value="B">B</option>
  <option value="-">Other</option>
</select>

<input type="text" name="other">
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This mechanism works in all browsers and requires no JavaScript.

You could use a little JavaScript to be clever about only showing the input if the "Other" option was selected.

datalist Element

The datalist element is intended to provide a better mechanism for this concept. In some browsers, e.g. iOS Safari < 12.2, this was not supported or the implementation had issues. Check the Can I Use page to see current datalist support.

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<input type="text" name="example" list="exampleList">
<datalist id="exampleList">
  <option value="A">  
  <option value="B">
</datalist>
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