Autocomplete - typehead
The Typeahead plugin from Twitter's Bootstrap 2 ready to use with Bootstrap 3 and Bootstrap 4. Full documentation can be found: https://github.com/bassjobsen/Bootstrap-3-Typeahead

Basic example via data attributes: (type 'item...')

<input type="text"
data-provide="typeahead"
data-source='["item 1","item 2","item 3"]'
placeholder="item..."
class="form-control" />

Load collection from json file (type 'Arg...')

$.get('https://cruz.site44.com/js/api/typehead_collection.json', function(data){
    $(".typeahead_2").typeahead({ source:data.countries });
},'json'); 

Basic example via javascript (type 'item...')

$('.typeahead_1').typeahead({
    source: ["item 1","item 2","item 3"]
}); 

Load json object - required 'name' attribute (type 'Afg...')

$('.typeahead_3').typeahead({
    source: [
        {"name": "Afghanistan", "code": "AF", "ccn0": "040"},
        {"name": "Land Islands", "code": "AX", "ccn0": "050"},
        {"name": "Albania", "code": "AL","ccn0": "060"},
        {"name": "Algeria", "code": "DZ","ccn0": "070"}
    ]
}); 

Options can be passed via data attributes or JavaScript. For data attributes, append the option name to data-, as in data-source="".

Name	Type	Default	Description
source	array, function	[ ]	The data source to query against. May be an array of strings, an array of JSON object with a name property or a function. The function accepts two arguments, the query value in the input field and the process callback. The function may be used synchronously by returning the data source directly or asynchronously via the process callback's single argument.
items	number	8	The max number of items to display in the dropdown. Can also be set to 'all'
minLength	number	1	The minimum character length needed before triggering autocomplete suggestions. You can set it to 0 so suggestion are shown even when there is no text when lookup function is called.
showHintOnFocus	boolean	false	If hints should be shown when applicable as soon as the input gets focus.
scrollHeight	number, function	0	Number of pixels the scrollable parent container scrolled down (scrolled out the viewport).
matcher	function	case insensitive	The method used to determine if a query matches an item. Accepts a single argument, the item against which to test the query. Access the current query with this.query. Return a boolean true if query is a match.
sorter	function	exact match, case sensitive, case insensitive	Method used to sort autocomplete results. Accepts a single argument items and has the scope of the typeahead instance. Reference the current query with this.query.
updater	function	returns selected item	The method used to return selected item. Accepts a single argument, the item and has the scope of the typeahead instance.
highlighter	function	highlights all default matches	Method used to highlight autocomplete results. Accepts a single argument item and has the scope of the typeahead instance. Should return html.
displayText	function	item.name || item	Method used to get textual representation of an item of the sources. Accepts a single argument item and has the scope of the typeahead instance. Should return a String.
autoSelect	boolean	true	Allows you to dictate whether or not the first suggestion is selected automatically. Turning autoselect off also means that the input won't clear if nothing is selected and enter or tab is hit.
afterSelect	function	$.noop()	Call back function to execute after selected an item. It gets the current active item in parameter if any.
delay	integer	0	Adds a delay between lookups.
addItem	JSON object	false	Adds an item to the end of the list, for example "New Entry". This could be used, for example, to pop a dialog when an item is not found in the list of data. Example: http://cl.ly/image/2u170I1q1G3A/addItem.png