hello-typeahead.html

<html>

    <head>
        <script>
            var autocompleteWords = [ 
                "Tomer", "To be or not to be", "Coc is the best",
                "Coc is awesome",
                "Hummus", "GT" ];
            function complete(event) {
                console.log("GOT ONE");
                if(this.value && !event.ctrlKey) {
                  var text = this.value.toLowerCase();
                  for(var i = 0; i < autocompleteWords.length; i++) {
                     if(autocompleteWords[i].toLowerCase().indexOf(text) === 0) {
                        this.value = autocompleteWords[i];
                        this.setSelectionRange(text.length, autocompleteWords[i].length);
                        break;
                     }
                  }
                }
            }
            window.onload = function() { // anonymous function
                var inputBox = document.getElementById("typeahead");
                inputBox.onkeyup = complete;
            }

        </script>

    </head>
    
    <body>
        <h1>Autocomplete typeahead</h1>
        <input type="text" id="typeahead" placeholder="Type Here"></input>
    </body>

</html>