Develop Reference

Restore native Window method

For a script I'm writing, I'd like to use the native window.open method. However, a script already loaded to which I don't have access, overwrites the global window.open method with a boolean (ouch).
I know how to restore the methods on the Document (via HTMLDocument.prototype), but I don't know how to restore them on the Window, as I can't seem to find the equivalent for that to Window. Window.prototype.open does not exist for example.
I have tried creating an iframe, and getting the open method from that contentWindow in the iframe, but the browser will block opening windows using open because it was probably created in another origin. Neither delete open; does work because open was defined using var in the globally loaded script.
So, how can I restore the open method, defined as 'native code' in Chrome?
I know there are similar questions around, but actually the main question is:
Is there a equivalent of HTMLDocument for the Window object?

I've found this question and the accepted answer (using an iframe) could be used in your case.
The only issue is you can only use the retrieved version of window.open as long as the iframe is still in your document.
function customOpen() {
// local variables definitions :
var url = "https://stackoverflow.com", iframe, _window;
// creating an iframe and getting its version of window.open :
iframe = document.createElement("iframe");
document.documentElement.appendChild(iframe);
_window = iframe.contentWindow;
// storing it in our window object
window.nativeOpen = _window.open;
try {
window.open(url);
} catch (e) {
console.warn(e); // checking that window.open is still broken
}
window.nativeOpen(url);
// deleting the iframe :
document.documentElement.removeChild(iframe);
}
document.getElementById("button").addEventListener("click", customOpen);
Another JSFiddle
Keeping the workaround answer in case someone needs it :
Can you execute a custom script prior to the execution of the script that redefines window.open? If so, you could create a copy of the window.open in another global variable.
It could look like this :
1. First : a backup script
window.nativeOpen = window.open;
2. Then, whatever the window.open overwriting script does :
window.open = false; // who does that, seriously?
3. Your window opening script, that'll use your window.open copy :
function customOpen() {
var url = "https://stackoverflow.com";
try {
window.open(url);
} catch (e) {
console.warn(e);
}
window.nativeOpen(url);
}
JSFiddle example

Check if window is already open window.open

I have a html page. In the body of the page I am calling onload event which calls javascript function to open a pop up window. here is the code:
var newWindow = null;
function launchApplication()
{
if ((newWindow == null) || (newWindow.closed))
{
newWindow = window.open('abc.html','','height=960px,width=940px');
}
}
when I move to another page, and come back to that page again, popup reopens, although it is already opened. Please guide me to proper direction so that if pop up is already open then it should not open again. I tried document.referred but it requires the site online, currently I am working offline.

newWindow = window.open('abc.html','com_MyDomain_myWindowForThisPurpose','height=960px,width=940px');
Give the window a name. Basing the name on your domain like this, prevents the chances of you picking a name someone else happened to choose.
Never make up a name that begins with _, those are reserved for special names the browser treats differently (same as with the "target" attribute of anchor elements).
Note that if the window of that name was opened with different options (e.g. different height), then it'll keep those options. The options here will only take effect if there is no window of that name, so you do create a new one.
Edit:
Note that the "name" is of the window, not of the content. It doesn't affect the title (newWindow.document.title will affect that, as of course will code in abc.html). It does affect other attempts to do stuff across windows. Hence another window.open with the same name will reuse this window. Also a link like clicky! will re-use it. Normal caveats about browsers resisting window-opening in various scenarios (popup-blocking) apply.

To open a window and keep a reference to it between page refresh.
var winref = window.open('', 'MyWindowName', '');
if(winref.location.href === 'about:blank'){
winref.location.href = 'http://example.com';
}
or in function format
function openOnce(url, target){
// open a blank "target" window
// or get the reference to the existing "target" window
var winref = window.open('', target, '');
// if the "target" window was just opened, change its url
if(winref.location.href === 'about:blank'){
winref.location.href = url;
}
return winref;
}
openOnce('http://example.com', 'MyWindowName');

You can check if the window is open or closed by re-assigning a reference to it when it closes. Example:
var newWindow;
var openWindow = function(){
newWindow = newWindow || window.open('newpage.html');
newWindow.focus();
newWindow.onbeforeunload = function(){
newWindow = null;
};
};

Use the "closed" property: if a window has been closed its closed property will be true.
https://developer.mozilla.org/en-US/docs/Web/API/Window/closed

When you move on another page (on the same domain), you can re-set the window.open variable with popup page like this :
https://jsfiddle.net/u5w9v4gf/
Step to try :
Click on Run (on jsfiddle editor).
Click on Try me (on preview).
Click on Run to move on another page, the variable will be re-set.
Code :
window.currentChild = false;
$("#tryme").click(function() {
if (currentChild) currentChild.close();
const child = window.open("about:blank", "lmao", 'width=250,height=300');
currentChild = child;
//Scrope script in child windows
child.frames.eval(`
setInterval(function () {
if (!window.opener.currentChild)
window.opener.currentChild = window;
}, 500);
`);
});
setInterval(function() {
console.log(currentChild)
if (!currentChild || (currentChild && currentChild.closed))
$("p").text("No popup/child. :(")
else
$("p").text("Child detected !")
}, 500);

JavaScript - Reference Browser Window by name? [duplicate]

This question already has answers here:
Access a window by window name
(7 answers)
Closed 4 years ago.
When you create a new browser window, you pass it a name like this:
myWindow = window.open('http://www.google.com', "googleWindow");
Later you can access the window from the variable you saved it as:
myWindow.close();
Is it possible to access and manipulate a window by it's name (googleWindow) instead of the variable?
If it is not possible, what is the point giving windows names?

No. Without a reference to the window, you can't find it again, by name or otherwise. There is no collection of windows.
UPDATE: Here's how you could do it yourself:
var windows = {};
function openWindow(url, name, features) {
windows[name] = window.open(url, name, features);
return windows[name];
}
Now, openWindow will always open the window, and if the window already exists, it will load the given URL in that window and return a reference to that window. Now you can also implement findWindow:
function findWindow(name) {
return windows[name];
}
Which will return the window if it exists, or undefined.
You should also have closeWindow, so you don't keep references to windows that you opened yourself:
function closeWindow(name) {
var window = windows[name];
if(window) {
window.close();
delete windows[name];
}
}
If it is not possible, what is the point giving windows names?
The name is used internally by the browser to manage windows. If you call window.open with the same name, it won't open a new window but instead load the URL into the previously opened window. There are a few more things, from MDN window.open():
If a window with the name strWindowName already exists, then strUrl is loaded into the existing window. In this case the return value of the method is the existing window and strWindowFeatures is ignored. Providing an empty string for strUrl is a way to get a reference to an open window by its name without changing the window's location. To open a new window on every call of window.open(), use the special value _blank for strWindowName.

Linus G Thiel says that you cannot do this in javascript. Oddly enough, his answer lists an excerpt from MDN that sounds like it tells how to do this. The line was:
"Providing an empty string for strUrl is a way to get a reference to
an open window by its name without changing the window's location."
I tried this and it works for me.
winref = window.open('', 'thatname', '', true);
winref.close();
However, this may only work if you opened the window from your page. And if that's true, then it's kind of pointless to do a window.open just to get the reference. You probably already have the reference, in that case.

Mark Goldfain's solution no longer works as written as of 9/8/2015
As per this w3 specification,
If the first argument is the empty string, then the url argument must
be interpreted as "about:blank".
I believe this is a difference between HTML4 and HTML5.
IE and Chrome have updated this behavior to match this specification, while Mark's solution still works on FF (though I imagine that they'll fix this soon). A few weeks ago this worked on all major browsers.
My particular problem involved window control while navigating, where the chat window opening is black boxed as well as most of the code on the page - redefining window.open was right out. My solution involved calling the blank window with the reference before calling the function which called the chat window. When the user navigated away from the page, I was able to rely on the fact that windows other than the original parent are not allowed to modify the child window, and so I was able to use Mark Goldfain's solution unchanged.

The solution provided by Mark Goldfain can be edited to work with the new browsers, at least to open a window and keep a reference to it between page refresh.
var winref = window.open('', 'MyWindowName', '', true);
if(winref.location.href === 'about:blank'){
winref.location.href = 'http://example.com';
}
or in function format
function openOnce(url, target){
// open a blank "target" window
// or get the reference to the existing "target" window
var winref = window.open('', target, '', true);
// if the "target" window was just opened, change its url
if(winref.location.href === 'about:blank'){
winref.location.href = url;
}
return winref;
}
openOnce('http://example.com', 'MyWindowName');

I ended up using the following:
var newwindows = {};
function popitup(url, nm) {
if ((newwindows[nm] == null) || (newwindows[nm].closed)) {
newwindows[nm] = window.open(url, nm, 'width=1200,height=650,scrollbars=yes,resizable=yes');
}
newwindows[nm].focus();
}
then referenced using:
<button type="button" onclick="popitup('url/link.aspx?a=bc',this.value)" value="uniqueName">New</button>

Window.open doesn't return the window reference IE9

I'm using a script to mount my mailto link and call the default email editor. But I can't use document.location.href because of some bug in IE9, so I use window.open. It works. But I need to close the IE windows opened.
The problem is the window.close doesn't return the window reference.
function doMailto() {
var sMailto = 'mailto:?bcc=';
sMailto += document.getElementById('<%= txtEmails.ClientID %>').value;
out = window.open(sMailto);
out.close(); //CANT CALL CLOSE, BECAUSE OUT IS NULL
}

You have an extra paren at the end of the assignment line.
Also, are you trying to close the window in the same function as assigned? If not, you may need to declare the window variable outside the function so it can be closed when needed.

aside the syntax errors (two commas, two parentesis closing)...
you are opening a window that is external to the browser, your default mail client. You cannot control it through javascript.
Maybe it's an immediacy problem, try using:
var out = window.open()...
setTimeout(function(){out.close()}, 200)
and fiddle with the 200ms to see if it works then.
try
top.location.href = 'mailto:....';
you won't need to open or close any windows this way

How to check whetherpop up blocker is turned ON or not in a browser using Code ?

How to check whether pop up blocker is turned ON or not in a browser using java or Java script Code ?
function check ()
{
document.login.action= url+"test.jsp";
document.login.submit();
}
I will call this function on click of submit button

How about:
var myWindow = window.open (url);
if (if (myWindow == null || typeof(myWindow )=='undefined'))
{
// popup blocker is enabled
}
else
{
myWindow.close();
}

If you use window.open() to open the popup, check for the return value.
According to the MDC doc center (a good javascript reference) the return value is null if opening the window didn't succeed for whatever reason.
var windowReference = window.open(url);
See the documentation on window.open here.