JSFiddle - React, Tailwind, and code Playground

HTML

<input type=text name="textbox" id="textbox">
<select id="combobox">
<option value = 1>1</option>
<option value = 2>2</option>
<option value = 3>3</option>
</select>

CSS

#combobox {
    display : none
}

JavaScript

var box_timer;
$("#combobox").mouseout(function(){
    box_timer = setTimeout(function () {
        var box_val = $("#combobox").hide().val();
        $("#textbox").val(box_val).show();
    }, 100);
}).mouseover(function () {
    clearTimeout(box_timer);
});
$("#textbox").mouseover(function(){
    $("#combobox").show();
    $("#textbox").hide();
}).children().mouseover(function (event) {
    clearTimeout(box_timer);
}).mouseout(function () {
    box_timer = setTimeout(function () {
        $('#combobox').trigger('mouseout');
    }, 100);
});