Jump to content
  • Announcements

    • boen_robot

      Guidelines and Netiquette   03/28/2017

      Posting Problems:   Having problems posting your topic? Read through this: To join, you agree to our terms and conditions and fill out and submit a registration form. An activation email will be sent to your email adress, so you'll need to verify your account. After that the account has to be validated by one of the moderators. This will mean that it can take up to a day to be activated. A couple of things to remember to ensure approval: Don't use an email address in one of those $2 four character .com domains eg. xyds.com. These will be deleted and the domain added to the banned list. Don't use an email address that is within a domain with a bad reputation for spam. A Google search is run on every email address and email domain. Don't sign up with an email address that doesn't exist, doesn't work or requires the sender to answer a quiz before their email can get to you. Put your country and or state and city in the signup form. Blank forms will go to the botton of the "to do" list. And make sure that your email address and your country match, saying you're from Alabama and using a .ru email address is not going to get you activated. After a membership is activated the first few posts will be monitored. Posting spam or unapproved topics described in the agreement results in an immediate ban. The email provider and the IP addresses associated with the account will be banned and all posts will be deleted. These strict measures have been deemed necessary to hinder spam. Sorry for any inconvenience this causes, but it's not liable to change. If, after reading this, you still can't post and don't understand why, contact one of the Moderators listed here.   Topic Guidelines   Including the following information can expedite an accurate response from board members: Must be a Specific Problem or Question related to web design and development Include Code in Question (wrap with   for small blocks of code and for longer blocks   ) Include Code Author Include Extra Notes/Modifications/Attempts Include web link to page/file when possible Content Guidelines   You may not post, upload, link to, or email any Content that contains, promotes, gives instruction about, or provides prohibited Content. Prohibited Content includes any Content that breaks any local, state, county, national or international law. Prohibited Content also includes: No direct or indirect advertising or websites, forums, products, services No hijacking of posts (do not post your question in someone elses) Content that infringes upon any rights [ex. MP3s and ROMs] (including, but not limited to, copyrights and trademarks) Abusive, threatening, defamatory, racist, or obscene Viruses or any other harmful computer software False Information or libel Spam, chain letters, or Pyramid schemes Gambling or Illicit drugs Terrorism Hacking or cheating for internet/online games Warez, Roms, CD-Keys, Cracks, Passwords, or Serial Numbers Pornography, nudity, or sexual material of any kind Excessive profanity Invasive of privacy or impersonation of any person/entity Hacking materials or information Posting Tips   There are more BBcodes than there are buttons for on the reply menu. To get the full list, click "BB Code Help" underneath the clickable smilie face menu. Use   for small snippets of code Use   for lengthy snippets of code Use   if your snippet is HTML (optional) Use   if your snippet is SQL (optional) Rules of Conduct   Be nice. There's no need for calling someone stupid if they ask an 'easy' question. Keep your avatars and signatures absolutely child friendly. We have a younger audience on this forum. Keep your language appropriate for the same reason above. Do not PM moderators for help on the forum. Post on the topic, or create a new one.   Spam:   Recently, as you have all without doubt noticed, we have had lots of spam and advertisement on the forum. Therefore, we'd like to alert you as to what to do when you have found any of the aforementioned annoying messages: it. Immediately. Give a clear reason, please, if the advertising is not evident. DO NOT POST! Report, let the post stay as is, and we will get to it, meanwhile if you continue to post as normal in the other threads, it won't be on the top so long. Refrain from PMing the member. This won't help at all, as they are most likely spambots anyway. Thank you.       Images in signatures:   After thinking of users on dial-up, we have decided to enforce the following rules regarding signatures. Please pay heed to them. Respecting these rules is respecting the members on this forum with dial-up. Signature rules: No animated images AT ALL. No matter the amount of animation. Maximum image widthxheight: 300x150 Maximum image (file) size: 15kb Use calm colors. Do not use highly contrasting images in your signature, as this can get really annoying when seeing several posts from one member in the same thread. The same prohibited content goes for images as for posts. Lastly, use common sense. No lengthy signatures please. Save us some scrolling. Thank you.       Links in signatures:   Please understand that w3schools.com only exists because of voluntary work and is barely supported by the advertising littered throughout the tutorials and the forum. So, please, stop advertising other sites. DO not post links that drive traffic away from the w3schools domain - especially to a site that offers similar if not identical information. Please help support the site by keeping individuals on it. Thank you. Here are some guidelines as to what you can put in your signature: w3schools links --> allowed w3.org links --> allowed browser links --> allowed html editor links --> allowed personal sites --> allowed tutorial sites competing with w3schools --> NOT allowed sites completely irrelevant to webprogramming and this forum --> NOT allowed   Thanks for understanding, and for taking the time to read this. ~W3Schools Modstaff~
Sign in to follow this  

How to expose and isolate the getters/functions that define window innerWidth and innerHeight in Chrome?

Recommended Posts


I would like to define non-replaceable references/getters to the innerWidth and innerHeight properties of window, or whatever they reference and are updated by. This is because currently, I can very easily re-assign, delete or re-define these properties to any other value making them unreliable if they were accidentally tampered with.

In Mozilla, Object.getOwnPropertyDescriptor(window, x) where x is innerWidth or innerHeight, returns a descriptor of a configurable and enumerable property with a getter and setter containing functions that I can retrieve, bind to window and isolate.

However, in Chrome, the function returns a descriptor of a property that does not contain a getter or setter, but rather a value, that magically updates when the inner window is resized given that the property has never been manually re-assigned, re-defined or deleted.

Reading Mozilla Developer Network, I have found the specification that describes these two properties is that of the CSS Object Model ( link: https://drafts.csswg.org/cssom-view/#dom-window-innerwidth ). In this specification I have located the `partial interface Window` which defines these view-port properties as `[Replaceable] readonly attribute long` where the [Replaceable] means that the property can be re-assigned and will continue to indefinitely reference the new re-assigned value whilst keeping the same property name, despite it being read-only.

This explains the behavior I have seen in Chrome, however there seems to be no means to extract a function or generate a reference that I could potentially hide in a closure or a block and (not 100% but mostly) reliably use it as the true width and height of the inner-window in pixels.

Seeing as I can expose and isolate a getter in Mozilla, is there any (perhaps other) way to utilise a slightly safer means of getting the innerWidth and innerHeight of window? Because in terms of JavaScript, the two properties seem to be magical in how they update as doing something like Object.defineProperty(window, 'innerWidth', Object.assign(Object.getOwnPropertyDescriptor(window, 'innerWidth'), {writable: false, configurable: false}) does the same thing as re-assigning and then freezing the property afterward; nothing.

Kind Regards, Augustas.

Edited by Kreative

Share this post

Link to post
Share on other sites

It seems like Firefox doesn't treat it as a read-only property, despite the documentation. Chrome returns a value property without a getter and setter, which is what it sounds like it should do if it's a read-only non-accessor descriptor. Firefox returns a descriptor with a getter and setter but no value, which is the opposite. Their documentation doesn't seem that consistent either. On the MDN page for innerHeight here:




Under the Value heading it does say that the property is read-only. But in the list of properties for the Window object here:




Both innerHeight and innerWidth are not marked as read-only.


What problem are you trying to solve though? If you want to read the value of innerWidth or innerHeight for the window you can at any time, what else are you missing?

Share this post

Link to post
Share on other sites

Is it possible to generate a reference or obtain some function that I can hide, that gives innerWidth and innerHeight even if window.innerWidth and/or innerHeight have been replaced? Maybe this could be rephrased as: can the properties be made non-replaceable?

Share this post

Link to post
Share on other sites

If the browser doesn't natively do it, there's no way to protect the property. I would operate under the assumption that nobody's messing with window properties.


If it's your own code that's overriding the property then fix it. If you're dealing with somebody else's code that does that, you'll have to either rewrite it or stop using it.


I cannot imagine a situation where any developer would override these properties, if they're doing so, their code is not worth using.

Share this post

Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
Sign in to follow this