How to make a webpage play a sound - javascript

I need to make a sound from a webpage immediately after load (OK/NOT OK signal depending on the case). The page is generated and I can control the content fully.
How do I do this in a modern, cross browser compatible way? I've experienced problems with <audio> tag (maybe browser issues, maybe I'm doing it somehow wrong). Currently I use a small flash player, but as you might guess, it is not a perfect solution.
And yes, the sound is exactly what the user wants, so please no "website with sound is not a good idea" -comments. Generally I would agree, but there are special cases.

Using an audio element works in modern browsers, and for older browsers, you can use an embed fallback (which may or may not work, depending on installed plugins, but if it does not work, there is not much you can do):
<audio src=maamme.mp3 controls autoplay>
<embed src=maamme.mp3>
</audio>
This creates visible controls at the place where you put this element. You can modify those controls to some extent or hide them. If you want to control more exactly when the presentation starts, you can dynamically add the element into the document instead of having it statically there. If old browsers are not very relevant, you could alternatively use an audio element without autoplay and use the HTMLMediaElement interface to start the presentation, do things when it has ended, etc.

If you wish to control the audio yourself, you can do it programatically through javascript.
window.onload = function(){
var snd = new Audio("sound/mysound.wav");
snd.play();
}
This should load the audio file and play it automatically once the page has loaded. It should be noted however that iOS limits any audio being played like this, without a user interaction (e.g. a click) because it forces the user to use up bandwidth and takes control away from them. Android, and other devices may or may not allow autoplaying audio, but all latest web browsers on desktop allow it (Chrome, FF, IE9+, Safari)

Related

Is Javascript needed to play HTML 5 Videos in recent browsers?

Based on this page on w3schools I don't see any mention of Javascript being needed to play HTML5 videos on recent browsers.
https://www.w3schools.com/html/html5_video.asp
Yet, when I disable Javascript on Safari, I can no longer play Videos embedded on my webpage via Tag. I even disabled lazy loading on a test page to see if that helped, but it didn't.
My primary concern is visitors on Mobile devices so falling back to flash is not an option.
hence the question, Is Javascript needed on fairly recent browsers ? what are best fallback options without requiring any plugins ?
like, using to provide direct download of Video, etc ?
javascript is absolutely not required to play the video in html5
the w3 video is not playing because it is rendering that part of the dom using js and also video is not local it is brought by anchor tag

How can detect sound on webpage with JavaScript in PhantomJS?

I need detect all sound in webpage with banners. How I can do this?
I look to PhantomJS, but can't find a API for browser sound.
PhantomJS (1.x and 2) doesn't support either Flash, <video> or the <audio> element. There is no way to detect sound, because there isn't any.
From the docs:
Support for plugins (such as Flash) was dropped a long time ago.
and
Video and Audio would require shipping a variety of different codecs.

Seamlessly play video files in sequence with HTML <video>

I have tried several methods:
I tried to create hidden video tags and show/hide them, but this will cause flickering.
I tried to change the src attribute of the video, but I have to call load() method before play(), and the load() will load the new video.
This is not what I want either, because this causes the new video to stop for a while (because need time to load).
I tried to cache the new video by using ajax to load the new video in background before the previous video is finished. The new video can be downloaded completely (300Kbytes) before the old video is finished.
But when I call .load() function on the new video, it will be downloaded again.
My question is: for my third method, is there a way for the video object to make use of the downloaded file in cache?
After reading around, I think the above three are probably the only ways to realize my objective. The third one is really what I want but the video file just got downloaded twice (once is Ajax download, and another is calling load()). Note that, without calling load(), just simply changing the src attribute and calling play() will not work.
Media Source Extensions are what you need. It's hard to find good documentation on them yet (at the time of writing, MDN's documentation is mostly stubs), but you can delve into the spec if you dare.
The two-sentence summary is that with Media Source Extensions you can create a MediaSource object and set it as the source of a <video> element, instead of pointing the <video> at the URL of a complete video. Then you can use JavaScript to explicitly download videos representing further segments of your live stream and append them to your MediaSource object, and the segments will play seamlessly.
Also, while it's slightly beyond the scope of what you've asked here, MPEG-DASH is a technique for doing exactly what you're interested in (i.e. streaming live video by encoding short segments as individual files, such as short standalone mp4s, and serving these segments individually to the browser). There's no way to implement MPEG-DASH in a browser without Media Source Extensions, so they are often discussed together. There are some good writeups (at different levels of detail) on building a DASH player with HTML and JavaScript using Media Source Extensions on the BBC's tech blog and MSDN.
Unfortunately, Media Source Extensions are not yet available in all major browsers. For instance, the latest version of Firefox on my Mac doesn't have window.MediaSource. This means you can't do segmented live streaming in a way that will work on all major browsers using only a HTML 5 <video> element yet. Unfortunately, it's still necessary to fall back to Flash if you need cross-browser compatibility.
Like you, I tried to implement this behaviour without using Media Source Extensions. I tried (and tried combining) a whole bunch of techniques, including swapping out URLs on <video> elements, unhiding and playing <video> elements, downloading segments fully in advance and storing them in Blobs that I'd use as the src for my <video> elements, and setting the preload attribute to auto to load the segments into memory in advance... but nothing worked. In Google Chrome, using any of these techniques results in a visible stutter when you play() the second video from the first video's ended event, even if you've loaded the second video fully in advance. There just isn't a way to get seamless consecutive video playback using <video> elements without some kind of stutter in browsers that don't support Media Source Extensions.

Show controls while HTML5 video is playing

Is there a way to show the controls after a video has started playing. Basically, I'm playing a video with play(), and I want the controls to stay up for a few seconds. Currently (at least on my Android device), the controls fade once the video starts.
Toggling the controls attribute doesn't work, unfortunately.
HTML5 video on Android (iOS too) is not opened inline but in the native player (i.e. outside the browser), so the <video>-tag attributes have no control over what is going to happen in the player.
I don't know if it's possible to "hack" / set-up the native player so I guess you'll have to do research on that. I don't know of any way to remotely influence the behavior of the Android application unfortunately. In case you find out something it would be nice if you could let me know btw.
Also see a recent question of mine (which is rather discouraging unfortunately).

Is it possible to get firefox to play MP4s in the html5 video tag?

I know it is not right out of the box, but is there a hack anywhere that uses javascript, php, or even flash to play the MP4s if the html5 video tag isn't supported?
Yes, there are several frameworks / plugins.
http://videojs.com/ for example provides good fallback.
It basically detects if HTML5 video is available and if not, it uses a provided flash player automatically. To change the order of used engines, you can set the option:
_V_.options.techOrder = ["swfH5"];
which will use swf before HTML5
The compatibility chart has a list of all browsers/technologies available for playback.

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