// Get the <datalist> and <input> elements.
var dataList = document.getElementById('json-datalist');
var input = document.getElementById('ajax');
// Create a new XMLHttpRequest.
var request = new XMLHttpRequest();
// Handle state changes for the request.
request.onreadystatechange = function(response) {
if (request.readyState === 4) {
if (request.status === 200) {
// Parse the JSON
var jsonOptions = JSON.parse(request.responseText);
// Loop over the JSON array.
jsonOptions.forEach(function(item) {
// Create a new <option> element.
var option = document.createElement('option');
// Set the value using the item in the JSON array.
option.value = item;
// Add the <option> element to the <datalist>.
dataList.appendChild(option);
});
// Update the placeholder text.
input.placeholder = "e.g. datalist";
} else {
// An error occured :(
input.placeholder = "Couldn't load datalist options :(";
}
}
};
// Update the placeholder text.
input.placeholder = "Loading options...";
// Set up and make the request.
request.open('GET', 'https://s3-us-west-2.amazonaws.com/s.cdpn.io/4621/html-elements.json', true);
request.send();
