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 The World Wide Web 

Embedding

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Embedding Media

Embedding is the process of including media from other sources into your web sites.

"other documents" can include:

  • media files
    • images, sound, video
  • other HTML (pages or snippets)
  • advertisements
  • maps, graphs, charts
  • search box e.g. Google custom search

"embedding" is sometimes also called "including" or "transcluding"

Interactive Embedding

Sometimes you can use JavaScript to interact with the embedded file or app as if it were another User Interface element on your page!

For instance, you could programmatically pause and play an embedded audio clip, say, playing "hoorah!" when the user wins a game of Tic-Tac-Toe.

Or, if the user moves their location on an embedded Google Map, your app could be notified and find the city name and look up restaurants in that area on Yelp's API.

This lesson focuses on static embedding: displaying media and allowing the user to interact with it directly. The Interactive Embedding lesson focuses on interactive embedding: using JavaScript to pass messages between your page's scripts and the embedded media.

Embedding Images

<img src=''> is the original embed

MDN: img

Where does the media come from?

  • Usually images are served from the same web server as HTML.
  • Some web sites host images or other media for free or a small cost
    • images: flickr.com, imgur.com, 500px.com, etc.
    • video: YouTube.com, Vimeo.com, Wistia.com, etc.
    • audio: SoundCloud.com, etc.
  • a CDN hosts all sorts of media for you for $$$
    • Amazon AWS / CloudFront, CloudFlare, Akamai...

Image Types

There are many different types of images: * svg * png * ptg * psd * jpg * and the list goes on...

Let's focus on a few of the common types of images you'll find around the web; JPGs (or JPEGs), PNGs, and SVGs.

jpeg/jpg

  • One of the most common image types
  • relatively small file size
  • limited features
  • no transparency
  • pixel based (raster) image type
  • rectangular in shape

Note: JPGs and JPEGs are the same type of image, however when embedding them in your page you will need to make sure you are using the correct file extension otherwise your site won't be able to locate the image. Also case matters!

png

  • Similar in size to JPGs (though often slightly larger)
  • pixel based (raster) image type
  • supports transparent
  • rectangular in shape

Note: While PNGs can appear to be irregular in shape they are not, transparent sections will still block users from interacting with any content behind them

svg

SVG stands for standard vector graphic

  • VERY small file size
  • vector based image type
  • scales indefinitely
  • can be irregular in shape
  • Only covers the exact area it appears to cover

Lab: Embedding Images

Let's go to our trusty "example-html" directory, and add some images to make your page more engaging!

  • add in one image from an external source per section on your index.html document

    • There are many sites around the web that serve up placeholder images. PlaceKitten is the classic, though PlaceCage, and FillMurray are both hilarious

  • Choose an image from your computer to include on your About page

  • Create a subdirectory named "images" (or 'imgs', or 'pictures', or whatever name makes sense to you)

  • Place a copy of your chosen image into the newly created subdirectory.

  • Embed that image into your About page.

  • Bonus Challenge: What happens when you wrap an image in an anchor tag?

Embedding IFrames

<iframe> means "inline frame"

<iframe id="inlineFrameExample"
    title="Inline Frame Example"
    width="300"
    height="200"
    src="https://www.openstreetmap.org/export/embed.html?bbox=-0.004017949104309083%2C51.47612752641776%2C0.00030577182769775396%2C51.478569861898606&layer=mapnik">
</iframe>

More Information

MDN IFrame Reference

Malware Vectors

Beware the "same origin policy":

Refused to display 'http://www.burlingtoncodeacademy.com/' in a frame because it set 'X-Frame-Options' to 'sameorigin'.
  • some web servers (e.g. Wordpress) set these headers on by default
  • other web servers (e.g. Apache) set these headers off by default

Beware giving foreign JavaScript access to your page contents and user-input data

  • the sandbox attribute limits what the loaded page can do

Embedding HTML snippets

You can use iframes to load the same HTML onto several pages on your site.

This is often used for login boxes.

Warning: iframes can take longer to load than the rest of the page, and can eat up CPU and RAM, so don't overuse them

Lab: Embedding an iFrame

iFrames are often used to embed videos from dedicated hosts such as Vimeo or YouTube

Let's add a video to our site! Open up YouTube, and find a short video, and a long video. Leave them open in different tabs.

  • Open up your "example-html" directory if it's not already open.
  • Go back to the open video tabs, and click on the "share" button
    • Choose the "embed" option, and copy the code for the iframe element it gives you
    • Paste that code into your index.html file
    • Play around with the options on the iFrame to modify the video's behavior/attributes

Embedding Flash

R I P Flash

"In July 2017, Adobe announced that it would declare Flash to be end-of-life in 2020, and will cease support, distribution, and security updates to Flash Player."

Modern Animations

Flash used to be the way to create web animations, but now we have better options

  • <canvas> elements using JavaScript
  • Pure CSS animations
  • The JavaScript animation api
  • Third party animation frameworks such as Snap SVG

Embedding Video

HTML5 defines a standard <video> tag

  • Use the <video> tag when you are hosting your own video media file (on your web server or a CDN)

  • video hosting sites like YouTube, and Vimeo have their own rules and sample code which you should find and copy into your HTML file

Tip: you can automatically start playing the video when the page loads; to be polite you should also mute the volume, like this: <video muted=true autoplay=true src='/videos/yelling-man.mp4'>

Embedding Audio

HTML5 also has a prebuilt <audio> tag that you can use to embed your local audio files into your web pages. There are several key attributes for audio elements.

  • src Like with all other forms of media the src attribut tells your tag where the actual audio file lives
  • autoplay Accepts a boolean value, when set to true it will begin playback as soon as it can
  • controls Adding this attribute with no value will display playback controls to the user
  • loop Another boolean attribute that repeats the audio indefinitely when set to true
  • muted Yet another boolean attribute. It mutes your audio when set to true

Playing Audio from JavaScript

Playing sounds directly from JavaScript is pretty easy:

let audio = new Audio('audio_file.mp3');
audio.play();

Embedding Maps

<iframe id="inlineFrameExample"
    title="Inline Frame Example"
    width="300"
    height="200"
    src="https://www.openstreetmap.org/export/embed.html?bbox=-73.2130900,44.4749000,-73.2102500,44.4772200&layer=mapnik">
</iframe>

OpenStreetMaps defines a "bounding box" as a four-tuple: min Longitude, min Latitude, max Longitude, max Latitude.

You can find the bounding box for a given map on https://www.openstreetmap.org/ by clicking the Export button.

Scripting Maps

It is possible to use JavaScript to interact with an embedded map. See the client-side coding lesson on embedding