javascript - Inject an opened window with script

Question

This question asks for a way to open a new window using window.open and then inject it with a script. It was not possible because of cross-domain security issues.

However, my problem is that I want to do the exact same thing, except from the same domain to the same domain. Is this possible?

Note that .write does not solve this problem because it wipes all the html from the page first.

Answer 1

You can do something like this:

var theWindow = window.open('http://stackoverflow.com'),
    theDoc = theWindow.document,
    theScript = document.createElement('script');
function injectThis() {
    // The code you want to inject goes here
    alert(document.body.innerHTML);
}
theScript.innerHTML = 'window.onload = ' + injectThis.toString() + ';';
theDoc.body.appendChild(theScript);

This also seems to work:

var theWindow = window.open('http://stackoverflow.com'),
    theScript = document.createElement('script');
function injectThis() {
    // The code you want to inject goes here
    alert(document.body.innerHTML);
}
// Self executing function
theScript.innerHTML = '(' + injectThis.toString() + '());';
theWindow.onload = function () {
    // Append the script to the new window's body.
    // Only seems to work with `this`
    this.document.body.appendChild(theScript);
};

And if for some reason you want to use eval:

var theWindow = window.open('http://stackoverflow.com'),
    theScript;
function injectThis() {
    // The code you want to inject goes here
    alert(document.body.innerHTML);
}
// Self executing function
theScript = '(' + injectThis.toString() + '());';
theWindow.onload = function () {
    this.eval(theScript);
};

What this does (Explanation for the first bit of code. All examples are quite similar):

• Opens the new window
• Gets a reference to the new window's document
• Creates a script element
• Places all the code you want to 'inject' into a function
• Changes the script's innerHTML to load said function when the window loads, with the window.onload event (you can also use addEventListener). I used toString() for convenience, so you don't have to concatenate a bunch of strings. toString basically returns the whole injectThis function as a string.
• Appends the script to the new window's document.body, it won't actually append it to the document that is loaded, it appends it before it loads (to an empty body), and that's why you have to use window.onload, so that your script can manipulate the new document.

It's probably a good idea to use window.addEventListener('load', injectThis.toString()); instead of window.onload, in case you already have a script within your new page that uses the window.onload event (it'd overwrite the injection script).

Note that you can do anything inside of the injectThis function: append DIVs, do DOM queries, add even more scripts, etc...

Also note that you can manipulate the new window's DOM inside of the theWindow.onload event, using this.