13. createObjectStore = function (dataBase) {
// Create an objectStore
dataBase.createObjectStore("elephants");
}
// Currently only in latest Firefox versions
request.onupgradeneeded = function (event) {
createObjectStore(event.target.result);
};
14. request.onsuccess = function (event) {
// Create XHR
var xhr = new XMLHttpRequest(),
blob;
xhr.open("GET", "elephant.png", true);
// Set the responseType to blob
xhr.responseType = "blob";
xhr.addEventListener("load", function () {
if (xhr.status === 200) {
// Blob as response
blob = xhr.response;
// Put the received blob into IndexedDB
putElephantInDb(blob);
}
}, false);
// Send XHR
xhr.send();
}
15. putElephantInDb = function (blob) {
// Open a transaction to the database
var transaction = db.transaction(["elephants"], IDBTransaction.READ_WRITE);
// Put the blob into the dabase
var put = transaction.objectStore("elephants").put(blob, "image");
// Retrieve the file that was just stored
transaction.objectStore("elephants").get("image").onsuccess = function (event) {
var imgFile = event.target.result;
// Get window.URL object
var URL = window.URL || window.webkitURL;
// Create and revoke ObjectURL
var imgURL = URL.createObjectURL(imgFile);
// Set img src to ObjectURL
var imgElephant = document.getElementById("elephant");
imgElephant.setAttribute("src", imgURL);
// Revoking ObjectURL
URL.revokeObjectURL(imgURL);
};
};
17. if (window.addEventListener) {
/*
Works well in Firefox and Opera with the
Work Offline option in the File menu.
Pulling the ethernet cable doesn't seem to trigger it
*/
window.addEventListener("online", isOnline, false);
window.addEventListener("offline", isOffline, false);
}
else {
/*
Works in IE with the Work Offline option in the
File menu and pulling the ethernet cable
*/
document.body.ononline = isOnline;
document.body.onoffline = isOffline;
}
27. LiveConnect
Forever Frame
HTTP Long-Polling and XHR Streaming
What came before WebSockets?
AJAX
HTTP Polling
Cross Frame Communication
28. var ws = new WebSocket("ws://robertnyman.com/wsmagic");
// Send data
ws.send("Some data");
// Close the connection
ws.close();
29. var ws = new WebSocket("ws://robertnyman.com/wsmagic");
// When connection is opened
ws.onopen = function () {
console.log("Connection opened!");
};
// When you receive a message
ws.onmessage = function (evt) {
console.log(evt.data);
};
// When you close the connection
ws.onclose = function () {
console.log("Connection closed");
};
// When an error occurred
ws.onerror = function () {
console.log("An error occurred");
};
32. <!--
The multiple attribute allows for
uploading of multiple files
-->
<input id="files-upload" type="file" multiple>
33. var filesUpload = document.getElementById("files-upload");
filesUpload.onchange = function () {
// Access to data about all files
var files = this.files,
file;
for (var i=0, l=files.length; i<l; i++) {
file = file[i];
file.name; // Get the name of the file
file.size; // Get the size of the file, in bytes
file.type; // Get the type of the file
};
};
40. var someImg = document.getElementById("some-image"),
dropArea = document.getElementById("drop-area");
someImg.ondragstart = function (evt) {
var event = evt || window.event;
event.dataTransfer.setData("Text", this.getAttribute("alt"));
return false;
};
dropArea.ondragenter = function (evt) {
return false; “If the drop is to be
};
accepted, then this
dropArea.ondragover = function (evt) {
return false; event (dragover) has
};
to be canceled.”
dropArea.ondrop = function (evt) {
var text = event.dataTransfer.getData("Text");
event.cancelBubble = true; // For IE
return false;
};
41. someImg.ondragstart = function (evt) {
var event = evt || window.event;
event.dataTransfer.setDragImage(dragIcon, -10, -10);
return false;
};
55. takePicture.onchange = function (event) {
// Get a reference to the taken picture or chosen file
var files = event.target.files,
file;
if (files && files.length > 0) {
file = files[0];
// Get window.URL object
var URL = window.URL || window.webkitURL;
// Create ObjectURL
var imgURL = URL.createObjectURL(file);
// Set img src to ObjectURL
showPicture.src = imgURL;
// Revoke ObjectURL
URL.revokeObjectURL(imgURL);
}
};
64. // Get battery level in percentage
var batteryLevel = battery.level * 100 + "%";
// Get whether device is charging or not
var chargingStatus = battery.charging;
// Time until the device is fully charged
var batteryCharged = battery.chargingTime;
// Time until the device is discharged
var batteryDischarged = battery.dischargingTime;
65. battery.addEventLister("levelchange", function () {
// Device's battery level changed
}, false);
battery.addEventListener("chargingchange", function () {
// Device got plugged in to power, or unplugged
}, false);
battery.addEventListener("chargingtimechange", function () {
// Device's charging time changed
}, false);
battery.addEventListener("dischargingtimechange", function () {
// Device's discharging time changed
}, false);
