afterprint not detected while hidden printing in an iFrame - javascript

I've spent nearly 2 days googling and trying lots of example (even here in StackOverflow), and I don't find any way to fire the event "afterprint". It seems dead. I've found some fiddle, where it works, and when I try to reproduce on my system, it doesn't.
I am not sure what I'm doing wrong.
Here is the code I want to use:
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>PDF Printing</title>
</head>
<body>
<button id="myButton2" onClick="printPage('http://localhost/~user/testPDF.pdf')">Print Me 2</button><br>
<script type="text/javascript">
function closePrint () {
console.log("Ciao");
document.body.removeChild(this.__container__);
}
function printPage (sURL) {
var myButton = document.getElementById("myButton2");
myButton.disabled=true;
var printFrame = document.createElement("iframe");
printFrame.id = "printPDF2";
printFrame.style.display = 'none';
printFrame.src = sURL;
printFrame.onload = function() {
printFrame.contentWindow.addEventListener('afterprint', function(evt) {
console.log("yellow");
document.body.removeChild(iframe)
});
this.contentWindow.__container__ = this;
this.contentWindow.onbeforeunload = closePrint;
this.contentWindow.onafterprint = closePrint;
this.contentWindow.focus(); // Required for IE
this.contentWindow.print();
}
document.body.appendChild(printFrame);
}
</script>
</body>
</html>
I've tried also with the MediaDetect. And it doesn't work... (I used these links for inspiration: https://jsfiddle.net/5qbc1pzj/ and https://jsfiddle.net/anhhnt/nj851e52/) the JS console is empty... I get no "Ciao" or "yellow"...
I'm using a simple Apache server, and using the latest IE Edge (103.0.1264.62).
I am out of idea, could someone give me an idea, where to look at?
Thank you in advance.
Kind regards,
Alessandro

It doesn't work because detecting the print events only work for HTML-documents. The MIME type for PDF windows is application/pdf so it doesn't work. The events that are available on the window are not available to the <embed> like tags, as they are handled by the browser's default application for the type. Although the event occurs here, it is not bubbled back to the window. For more information, you can refer to this answer.
The only solution to this seems to create your own PDF viewer. For example, you can use PDF.js.

Related

Start multiple downloads and get feedback when download prompt window showed

I'm currently writing a little program that generates an html file and opens it with the default browser to start multiple downloads.
I don't want to open a tab/window for every download, so creating hidden iframes for the downloads seemed like a good solution.
I'm using onload on the iframes to find out if the download prompts for each download have shown up yet. This approach seems to be very unreliable in the Internet Explorer though.
So I'm wondering if there is there a way to fix this or maybe a better approach?
(Without libraries please.)
Here is my html/js code:
<!DOCTYPE html>
<!-- saved from url=(0016)http://localhost -->
<html><head>
<meta content="text/html;charset=utf-8" http-equiv="Content-Type">
<meta content="utf-8" http-equiv="encoding">
<title>Downloads</title>
<script>
"use strict";
var downloadsInfo = {
"http://download-installer.cdn.mozilla.net/pub/firefox/releases/26.0/win32/en-US/Firefox%20Setup%2026.0.exe":"Status: Connecting",
"http://download.piriform.com/ccsetup410.exe":"Status: Connecting"
};
var i = 0;
var iv = setInterval(function() {
i = ++i % 4;
var j = 0;
var finished = true;
for (var key in downloadsInfo) {
var value = downloadsInfo[key];
if (value != "Status: Download Started!") {
value = value+Array(i+1).join(".");
finished = false;
}
document.getElementsByTagName("div")[j].innerHTML = key+"<br/>"+value;
j = j+1;
}
if (finished) {
alert('Done! You can close this window/tab now.');
clearInterval(iv);
}
}, 800);
</script>
</head><body>
<h3>Please wait for your downloads to start and do not reload this site.</h3>
<div></div> <br/><br/>
<div></div> <br/><br/>
<iframe src="http://download-installer.cdn.mozilla.net/pub/firefox/releases/26.0/win32/en-US/Firefox%20Setup%2026.0.exe" onload="downloadsInfo['http://download-installer.cdn.mozilla.net/pub/firefox/releases/26.0/win32/en-US/Firefox%20Setup%2026.0.exe'] = 'Status: Download Started!';" style="display:none"></iframe>
<iframe src="http://download.piriform.com/ccsetup410.exe" onload="downloadsInfo['http://download.piriform.com/ccsetup410.exe'] = 'Status: Download Started!';" style="display:none"></iframe>
</body></html>
Quite simply you can't know whether a native browser download started. Every browser has different ways this is handled, the user may set up his browser to prompt the location or he might just let it auto download to the Downloads folder (the default in most browsers nowadays). If he's prompting for a location he might cancel by mistake, yet your setup would still claim the download started. So, no, there is no way whatsoever to reliably inform the user that they can close a tab once all downloads are started/finished... provided that you use the native browser download mechanism.
The way to achieve this effect would be possibly by first downloading the file using Javascript (requiring you to have access to those files, hotlinking to third party files is of course not an option then). To see this in action try downloading a file from mega.nz. I was planning on writing up how to do this by hand, but there is already a nice (quite outdated) answer outlining this.
If the intention is only to ensure that the download has started you could implement a trigger on the back end to note when the file has been accessed. In it's simplest form this would look like:
Page download.html requests file.php?location=[...]&randomHash=1234
Once file.php is actually loaded it will set a flag in memory or the database that randomHash id 1234 has started.
file.php redirects the page with a 302 header to the actual file location.
download.html checks periodically using Ajax whether flag randomHash=1234 has been raised. If so it knows the download has started.
Indeed IE is reported to not always behave nicely with the onload event handler of iframes. There is an active bug tracker record opened.
The problem is discussed in a number of places around the web, and what seems to be the most reliable solution is to have an indirect download with nested iframes: the iframe loads a HTML file with an iframe that loads the file to download. The reason for that is that IE does not seem to like iframes that point to something else than HTML. So if you have the possibility to do that in your program:
For each file to download, generate a HTML file with a body that looks like this:
<iframe src="http://filetodownload.exe" style="display:none"></iframe>
Store this file in a temporary folder, e.g. C:\tmp\filetodownload.html
In your "master" generated HTML file, replace the iframe source with this intermediate file:
<iframe src="C:\tmp\filetodownload.html"
onload="downloadsInfo['http://filetodownload.exe']='Status: Download Started!';"
style="display:none"></iframe>
That may do the trick. But following IE's tradition, this could or could not work depending on the case...
If it does not work, some solutions that have proved useful include:
Put the onload handler in a function, and write in the definition of the iframe: onload="return theonloadfunction()" (even if the function does not return anything)
Instead of using the onload attribute, attach the event handler in javascript, like so:
iframe = document.getElementById("theiframeid")
iframe.attachEvent("onload", theonloadfunction);`
Note that attachEvent is for IE only. If you want to support other browsers you will have to detect it and use addEventListener for the non-IE cases.
Finally, you may try combinations of two or more of these solutions :)
<html>
<head>
<meta content = 'text/html;charset=utf-8' http-equiv = 'Content-Type'>
<meta content = 'utf-8' http-equiv = 'encoding'>
<script>
/*
First, I removed the setInterval(). Since you rely on the onload property we can aswell just check it on each onload.
Second, I changed your downloadsInfo to an object array.
Also be aware while testing, that some browsers cache your cancel/block choice and do not reask again for the same url.
Additionally firefox does not fire on frame downloads.
Furthermore the alert in your test might not show for overlapping or setting reasons.
*/
var downloadsInfo = [
{url: "http://download-installer.cdn.mozilla.net/pub/firefox/releases/26.0/win32/en-US/Firefox%20Setup%2026.0.exe", Status: "Connecting"},
{url: "http://download.piriform.com/ccsetup410.exe", Status: "Connecting"}
];
//IE has a problem in sometimes merely firing the onload propery once, which we bypass by dynamically creating them
//It is also less limited.
function iframeConnect(){
for(var i=0, j=downloadsInfo.length; i<j; i++){
var tF = document.createElement('iframe');
tF.arrayIndex = i; //For convenience
tF.style.display = 'none';
//Normal load event, working in ie8-11, chrome, safari
tF.onload = function(){
iframeExecuted(this.arrayIndex);
};
//Workaround for firefox, opera and some ie9
tF.addEventListener('DOMSubtreeModified', function(){
iframeExecuted(this.arrayIndex);
}, false);
document.body.appendChild(tF);
tF.src = downloadsInfo[i].url;
}
}
function iframeExecuted(i){
downloadsInfo[i].Status = 'Executed';
var tStatus = iframeFinished();
var tE = document.querySelector('h3');
if (tStatus.Done) tE.innerHTML = 'Finished'
else tE.innerHTML = 'Processed ' + tStatus.Processed + ' of ' + tStatus.Started;
}
function iframeFinished(){
for(var i=0, j=downloadsInfo.length; i<j; i++){
if (downloadsInfo[i].Status != 'Executed') break;
}
//Note that the Processed value is not accurate, yet it solves is testing purpose.
return {Done: (i == j), Processed: i, Started: j}
}
</script>
</head>
<body onload = 'iframeConnect()'>
<h3>Please wait for your downloads to start and do not reload this site.</h3>
</body>
</html>

Move DOM Node to Popup Window

I am trying to move a DOM node from the "root" page to a new pop-up that is created via window.open(). Here is the code I am using.
var win = window.open('/Search/Print', 'printSearchResults'),
table = $('#printTable');
win.document.close();
setTimeout(function () {
var el = win.document.createElement("table");
el.innerHTML = table.html();
win.document.body.appendChild(el);
}, 40);
It works in Chrome, but in IE8, I receive the following error: "Unknown runtime error."
I've also tried it this way:
var p = window.open('/Search/Print', 'printSearchResults'),
table = $('#printTable');
setTimeout(function () {
p.document.body.appendChild(table.clone(false)[0]);
}, 100);
Doing it this way, I receive "No such interface supported" in IE8. Again, Chrome works fine.
Does anyone have a way to do what I'm trying to achieve?
Here is the HTML for the pop-up window just for the sake of completeness:
<!DOCTYPE html>
<html>
<head>
<title>Print Results</title>
</head>
<body>
</body>
</html>
I tested your code on IE9 ( and IE8/7 browser mode).
Instead of el.innerHTML = table.html();
using jquery $(el).html(table.html()); fixed the issue.
To be able to use iframes and new windows, you should initialise them with addres: about:blank, before you write() to them. Also note that loading/opening the window/frame takes time, so you cannot write to them at right away. set a timeout, or check onload.
Please see this answer for more info.
Good luck!

javascript mouse event compatibility issue between browsers

I am new to the web development. I have a code that's supposed to change images when clicked on the image, and change the image back when released. And also it counts how many times it is clicked. I was building and testing this code on Safari and I didn't had any problems. It works just as expected on Safari. However it does not work on Chrome and IE (I haven't tested any other browsers).
I was normally working with HTML5 Boilerplate however I reduced the code so that I can show here (This version doesn't work too).
I have given the code of the page below. What should I do to make it work on every browser. What is the reason that it acts differently on browsers?
Thanks in advance
<!html>
<html>
<head>
<title></title>
<script type="text/javascript">
var count = 0;
function incrementCount()
{
count++;
document.getElementById( "count").innerHTML = count;
}
function pushTheButton()
{
document.images("bigRedButton").src = "img/pressed.gif";
return true;
}
function releaseTheButton()
{
document.images("bigRedButton").src = "img/unpressed.gif";
return true;
}
</script>
</head>
<body>
<div role="main">
<p>
<img src = "img/unpressed.gif" name="bigRedButton" onmousedown="pushTheButton()" onmouseup="releaseTheButton()" onclick="incrementCount()"/>
</br>
Click Count:<p id="count">0</p>
</p>
</div>
</body>
</html>
When testing in Chrome, remember to use its JavaScript console to watch for errors. In this case, it returns the following:
Uncaught TypeError: Property 'images' of object # is not a function
Your problem is on lines 18 and 24, when you attempt to access document.images("bigRedButton") -- document.images is an array (or possibly an object), not a function. It should be:
document.images["bigRedButton"].src
I don't know why it worked on Safari.
http://www.w3schools.com/jsref/coll_doc_images.asp
document.images is documented a integer-indexed array of images.
To be really sure, you should use:
document.images[0].src = ...
Although accessing the image by using the name works in many cases as well.

Why would Chrome and Firefox handle Javascript links differently?

I have a web site that works perfectly in FireFox 9.0.1.
In Chrome 16, it fails catastrophically. Too many errors to go through them all.
However, to pick one problem to start with (and hope that it be a clue that will help illuminate the core issues), I have buttons that are driven by Javascript to simply take someone to a new page.
The code for these buttons is as simple as it gets:
var siteURL = "http://mywebsite.com/";
function goHome()
{
window.location = siteURL + "index.html";
}
In FireFox, if I click the button that executes this code, I get taken to index.html. Easy peasy.
In Chrome, if I click this button, I get a 404 error page that says:
The requested URL /undefinedindex.html was not found on this server.
Why are these browsers behaving differently?
How do I get Chrome to play along?
As requested in the comments, I put alert(siteURL); in the function.
Firefox outputs:
http://mywebsite.com/
Chrome outputs
undefined
This works in Chrome 16:
<!DOCTYPE HTML>
<html lang="en">
<head>
<meta charset="UTF-8">
<title></title>
<script type="text/javascript">
window.siteURL = "http://mywebsite.com/";
function goHome() {
console.log('moo?');
window.location.href = window.siteURL + "index.html";
}
</script>
</head>
<body>
go home
</body>
</html>
you should not use window.location. and instead assign the url to window.location.href
Therefore, it should have been
function goHome()
{
window.location.href = siteURL + "index.html";
}
And also...you get that 'undefined' value because you probably didn't assign any value to siteURL, or you forgot to declare it. make sure it really points to your current root url (if you want it to be)
If all browsers behaved exactly identical, I would be out of work.
It's impossible to tell what exactly goes wrong without seeing the complete code.
Judging from the snippet abobe, there must be some other function (in the same scope as goHome) that assigns undefined to siteURL and gets called prior to goHome

Possible to flash a Browser window using Javascript?

Like many programs flash their window on the taskbar / dock to alert the user to switch to the program,
Is it possible to flash the Browser window using Javascript? (FireFox-only scripts are also welcome)
This is useful for web-based Chat / Forum / Community-based software where there is lots of real-time activity.
#Hexagon Theory: Why would you ever rewrite the whole head element just to change the value of one element in the head? Your solution is horribly inefficient on multiple levels.
<html>
<head>
<link rel="icon" href="on.png" type="image/png" id="changeMe" />
<script type="text/javascript" src="flash.js"></script>
</head>
<body>
</body>
</html>
flash.js:
function Flasher(speed) {
var elem = document.getElementById('changeMe');
this.timer = setTimeout(function() {
elem.href = elem.href == 'on.png' ? 'off.png' : 'on.png';
}, speed);
this.stop = function() { clearTimeout(this.timer); }
}
/* sample usage
*
* var flasher = new Flasher(1000);
* flasher.stop();
*/
It didn't really have to be a class but it helped keep the global namespace clean. That's untested but if simply changing the href doesn't work for some reason, clone the link node, change the href and replace the old link with the cloned one.
At this point, it seems only causing an alert dialog to pop up does the trick... this seems a bit too intrusive, I feel, particularly given the use you're trying to put it to. Instead of causing it to flash, though, you could modify document.title to grab the user's attention, either by prepending some signal (perhaps the string "NEW!") to the site's name, and then using an interval to constantly change it to "", which would then give a nice little "flashing" illusion.
Bare-bones example:
<html>
<head>
<title>Chat System</title>
<script>
var timer, old_t = document.title, blink_amount = 5, cur_b = 0;
function notify()
{
cur_b = 0;
timer = setInterval(function()
{
if (cur_b < blink_amount * 2)
{
cur_b++;
document.title = (document.title.indexOf('NEW! ') != -1) ? old_t : 'NEW! ' + old_t;
}
else
{
clearInterval(timer);
}
}, 600);
}
notify();
// From here, it's just a matter of calling the
// notify() function whenever you detect a new message.
</script>
</head>
<body>
</body>
</html>
Hey, another interesting solution to this question hit me just now. Why not really grab the user's attention by making the icon flash in their browser? You could, for example, make two icons (on.png and off.png in my example below) and repeatedly swap them out to really catch a user's eye. The following is a bare-bones implementation; do keep in mind that you will need to reference this script remotely or put it in the body of the page because it uses a method that repeatedly replaces the content of the <head> tag. Give it a try, though; I rather like the simplicity of it.
page.html:
<html>
<head>
<link rel="icon" href="on.png" type="image/png" />
<script type="text/javascript" src="flash.js"></script>
</head>
<body>
</body>
</html>
flash.js:
var timer, speed = 175;
function flash()
{
head_html = document.getElementsByTagName('head')[0].innerHTML;
if (head_html.indexOf('href="on.png"') != -1)
document.getElementsByTagName('head')[0].innerHTML = head_html.replace('on.png', 'off.png');
else
document.getElementsByTagName('head')[0].innerHTML = head_html.replace('off.png', 'on.png');
timer = setTimeout('flash()', speed);
}
function kill_flash() {clearTimeout(timer);}
flash();
Mozilla previously had Window.getAttention() but by 2018 no browsers were listed supporting it. https://web.archive.org/https://developer.mozilla.org/en-US/docs/Web/API/Window/getAttention
Its behavior:
Windows, the taskbar button for the window flashes
Linux, some window managers flash the taskbar button, others focus the window immediately
Macintosh, the icon in the upper right corner of the desktop flashes
Window.Focus() should do it on Windows, not sure on other platforms though. You might find it brings the Window to the foreground if it's minimised though, which would be very annoying :)

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