How to input text in HTML Select Tag?

Answer 1

Select elements can't contain anything other than option or optgroup elements. Here's a ref to the spec http://www.w3.org/TR/html5/forms.html#the-select-element

You may be better off adding an option for "other" in your dropdown and then using JS to detect for that choice to dynamically show an input (below the dropdown) for a custom value.