`. So, popups is not something we use everyday.
@@ -15,7 +15,7 @@ Also, popups are tricky on mobile devices, that don't show multiple windows simu
Still, there are tasks where popups are still used, e.g. for OAuth authorization (login with Google/Facebook/...), because:
-1. A popup is a separate window with its own independent JavaScript environment. So opening a popup with a third-party non-trusted site is safe.
+1. A popup is a separate window which has its own independent JavaScript environment. So opening a popup from a third-party, non-trusted site is safe.
2. It's very easy to open a popup.
3. A popup can navigate (change URL) and send messages to the opener window.
@@ -69,7 +69,7 @@ name
: A name of the new window. Each window has a `window.name`, and here we can specify which window to use for the popup. If there's already a window with such name -- the given URL opens in it, otherwise a new window is opened.
params
-: The configuration string for the new window. It contains settings, delimited by a comma. There must be no spaces in params, for instance: `width:200,height=100`.
+: The configuration string for the new window. It contains settings, delimited by a comma. There must be no spaces in params, for instance: `width=200,height=100`.
Settings for `params`:
@@ -89,7 +89,7 @@ There is also a number of less supported browser-specific features, which are us
## Example: a minimalistic window
-Let's open a window with minimal set of features just to see which of them browser allows to disable:
+Let's open a window with minimal set of features, just to see which of them browser allows to disable:
```js run
let params = `scrollbars=no,resizable=no,status=no,location=no,toolbar=no,menubar=no,
@@ -192,7 +192,7 @@ newWindow.onload = function() {
```
-## Scrolling and resizing
+## Moving and resizing
There are methods to move/resize a window:
@@ -237,21 +237,23 @@ There's also `window.onscroll` event.
## Focus/blur on a window
-Theoretically, there are `window.focus()` and `window.blur()` methods to focus/unfocus on a window. Also there are `focus/blur` events that allow to focus a window and catch the moment when the visitor switches elsewhere.
+Theoretically, there are `window.focus()` and `window.blur()` methods to focus/unfocus on a window. And there are also `focus/blur` events that allow to catch the moment when the visitor focuses on a window and switches elsewhere.
-In the past evil pages abused those. For instance, look at this code:
+Although, in practice they are severely limited, because in the past evil pages abused them.
+
+For instance, look at this code:
```js run
window.onblur = () => window.focus();
```
-When a user attempts to switch out of the window (`blur`), it brings it back to focus. The intention is to "lock" the user within the `window`.
+When a user attempts to switch out of the window (`window.onblur`), it brings the window back into focus. The intention is to "lock" the user within the `window`.
-So, there are limitations that forbid the code like that. There are many limitations to protect the user from ads and evils pages. They depend on the browser.
+So browsers had to introduce many limitations to forbid the code like that and protect the user from ads and evils pages. They depend on the browser.
-For instance, a mobile browser usually ignores that call completely. Also focusing doesn't work when a popup opens in a separate tab rather than a new window.
+For instance, a mobile browser usually ignores `window.focus()` completely. Also focusing doesn't work when a popup opens in a separate tab rather than a new window.
-Still, there are some things that can be done.
+Still, there are some use cases when such calls do work and can be useful.
For instance:
diff --git a/3-frames-and-windows/03-cross-window-communication/article.md b/3-frames-and-windows/03-cross-window-communication/article.md
index 53f5f55fc..091a0cecb 100644
--- a/3-frames-and-windows/03-cross-window-communication/article.md
+++ b/3-frames-and-windows/03-cross-window-communication/article.md
@@ -263,7 +263,7 @@ The window that wants to send a message calls [postMessage](mdn:api/Window.postM
Arguments:
`data`
-: The data to send. Can be any object, the data is cloned using the "structured cloning algorithm". IE supports only strings, so we should `JSON.stringify` complex objects to support that browser.
+: The data to send. Can be any object, the data is cloned using the "structured serialization algorithm". IE supports only strings, so we should `JSON.stringify` complex objects to support that browser.
`targetOrigin`
: Specifies the origin for the target window, so that only a window from the given origin will get the message.
diff --git a/3-frames-and-windows/03-cross-window-communication/sandbox.view/index.html b/3-frames-and-windows/03-cross-window-communication/sandbox.view/index.html
index 478830610..46dd7b5cc 100644
--- a/3-frames-and-windows/03-cross-window-communication/sandbox.view/index.html
+++ b/3-frames-and-windows/03-cross-window-communication/sandbox.view/index.html
@@ -7,7 +7,7 @@
-
The iframe below is has sandbox attribute.
+
The iframe below has the sandbox attribute.
diff --git a/4-binary/01-arraybuffer-binary-arrays/article.md b/4-binary/01-arraybuffer-binary-arrays/article.md
index 278f41f73..accd3c505 100644
--- a/4-binary/01-arraybuffer-binary-arrays/article.md
+++ b/4-binary/01-arraybuffer-binary-arrays/article.md
@@ -34,7 +34,7 @@ A view object does not store anything on it's own. It's the "eyeglasses" that gi
For instance:
-- **`Uint8Array`** -- treats each byte in `ArrayBuffer` as a separate number, with possible values are from 0 to 255 (a byte is 8-bit, so it can hold only that much). Such value is called a "8-bit unsigned integer".
+- **`Uint8Array`** -- treats each byte in `ArrayBuffer` as a separate number, with possible values from 0 to 255 (a byte is 8-bit, so it can hold only that much). Such value is called a "8-bit unsigned integer".
- **`Uint16Array`** -- treats every 2 bytes as an integer, with possible values from 0 to 65535. That's called a "16-bit unsigned integer".
- **`Uint32Array`** -- treats every 4 bytes as an integer, with possible values from 0 to 4294967295. That's called a "32-bit unsigned integer".
- **`Float64Array`** -- treats every 8 bytes as a floating point number with possible values from
5.0x10-324 to
1.8x10308.
@@ -77,7 +77,7 @@ Please note, there's no constructor called `TypedArray`, it's just a common "umb
When you see something like `new TypedArray`, it means any of `new Int8Array`, `new Uint8Array`, etc.
-Typed array behave like regular arrays: have indexes and iterable.
+Typed arrays behave like regular arrays: have indexes and are iterable.
A typed array constructor (be it `Int8Array` or `Float64Array`, doesn't matter) behaves differently depending on argument types.
@@ -209,7 +209,7 @@ These methods allow us to copy typed arrays, mix them, create new arrays from ex
## DataView
-[DataView](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/DataView) is a special super-flexible "untyped" view over `ArrayBuffer`. It allows to access the data on any offset in any format.
+[DataView](mdn:/JavaScript/Reference/Global_Objects/DataView) is a special super-flexible "untyped" view over `ArrayBuffer`. It allows to access the data on any offset in any format.
- For typed arrays, the constructor dictates what the format is. The whole array is supposed to be uniform. The i-th number is `arr[i]`.
- With `DataView` we access the data with methods like `.getUint8(i)` or `.getUint16(i)`. We choose the format at method call time instead of the construction time.
@@ -235,7 +235,7 @@ let dataView = new DataView(buffer);
// get 8-bit number at offset 0
alert( dataView.getUint8(0) ); // 255
-// now get 16-bit number at offset 0, it consists of 2 bytes, together iterpreted as 65535
+// now get 16-bit number at offset 0, it consists of 2 bytes, together interpreted as 65535
alert( dataView.getUint16(0) ); // 65535 (biggest 16-bit unsigned int)
// get 32-bit number at offset 0
@@ -244,7 +244,7 @@ alert( dataView.getUint32(0) ); // 4294967295 (biggest 32-bit unsigned int)
dataView.setUint32(0, 0); // set 4-byte number to zero, thus setting all bytes to 0
```
-`DataView` is great when we store mixed-format data in the same buffer. E.g we store a sequence of pairs (16-bit integer, 32-bit float). Then `DataView` allows to access them easily.
+`DataView` is great when we store mixed-format data in the same buffer. For example, when we store a sequence of pairs (16-bit integer, 32-bit float), `DataView` allows to access them easily.
## Summary
@@ -259,7 +259,7 @@ To do almost any operation on `ArrayBuffer`, we need a view.
- `Float32Array`, `Float64Array` -- for signed floating-point numbers of 32 and 64 bits.
- Or a `DataView` -- the view that uses methods to specify a format, e.g. `getUint8(offset)`.
-In most cases we create and operate directly on typed arrays, leaving `ArrayBuffer` under cover, as a "common discriminator". We can access it as `.buffer` and make another view if needed.
+In most cases we create and operate directly on typed arrays, leaving `ArrayBuffer` under cover, as a "common denominator". We can access it as `.buffer` and make another view if needed.
There are also two additional terms, that are used in descriptions of methods that operate on binary data:
- `ArrayBufferView` is an umbrella term for all these kinds of views.
diff --git a/4-binary/02-text-decoder/article.md b/4-binary/02-text-decoder/article.md
index fe9b8c042..3d836e6c0 100644
--- a/4-binary/02-text-decoder/article.md
+++ b/4-binary/02-text-decoder/article.md
@@ -12,7 +12,7 @@ let decoder = new TextDecoder([label], [options]);
- **`label`** -- the encoding, `utf-8` by default, but `big5`, `windows-1251` and many other are also supported.
- **`options`** -- optional object:
- **`fatal`** -- boolean, if `true` then throw an exception for invalid (non-decodable) characters, otherwise (default) replace them with character `\uFFFD`.
- - **`ignoreBOM`** -- boolean, if `true` then ignore BOM (an optional byte-order unicode mark), rarely needed.
+ - **`ignoreBOM`** -- boolean, if `true` then ignore BOM (an optional byte-order Unicode mark), rarely needed.
...And then decode:
diff --git a/4-binary/03-blob/article.md b/4-binary/03-blob/article.md
index 062e1834b..a44308f6f 100644
--- a/4-binary/03-blob/article.md
+++ b/4-binary/03-blob/article.md
@@ -55,7 +55,7 @@ This behavior is similar to JavaScript strings: we can't change a character in a
## Blob as URL
-A Blob can be easily used as an URL for `
`, `![]()
` or other tags, to show its contents.
+A Blob can be easily used as a URL for ``, `![]()
` or other tags, to show its contents.
Thanks to `type`, we can also download/upload `Blob` objects, and the `type` naturally becomes `Content-Type` in network requests.
@@ -97,9 +97,9 @@ That's what the value of `link.href` looks like:
blob:https://javascript.info/1e67e00e-860d-40a5-89ae-6ab0cbee6273
```
-The browser for each URL generated by `URL.createObjectURL` stores an the URL -> `Blob` mapping internally. So such URLs are short, but allow to access the `Blob`.
+For each URL generated by `URL.createObjectURL` the browser stores a URL -> `Blob` mapping internally. So such URLs are short, but allow to access the `Blob`.
-A generated URL (and hence the link with it) is only valid within the current document, while it's open. And it allows to reference the `Blob` in `![]()
`, ``, basically any other object that expects an url.
+A generated URL (and hence the link with it) is only valid within the current document, while it's open. And it allows to reference the `Blob` in `![]()
`, ``, basically any other object that expects a URL.
There's a side-effect though. While there's a mapping for a `Blob`, the `Blob` itself resides in the memory. The browser can't free it.
@@ -119,7 +119,7 @@ An alternative to `URL.createObjectURL` is to convert a `Blob` into a base64-enc
That encoding represents binary data as a string of ultra-safe "readable" characters with ASCII-codes from 0 to 64. And what's more important -- we can use this encoding in "data-urls".
-A [data url](https://developer.mozilla.org/en-US/docs/Web/HTTP/Basics_of_HTTP/Data_URIs) has the form `data:[][;base64],`. We can use such urls everywhere, on par with "regular" urls.
+A [data url](mdn:/http/Data_URIs) has the form `data:[][;base64],`. We can use such urls everywhere, on par with "regular" urls.
For instance, here's a smiley:
@@ -151,7 +151,7 @@ reader.onload = function() {
};
```
-Both ways of making an URL of a `Blob` are usable. But usually `URL.createObjectURL(blob)` is simpler and faster.
+Both ways of making a URL of a `Blob` are usable. But usually `URL.createObjectURL(blob)` is simpler and faster.
```compare title-plus="URL.createObjectURL(blob)" title-minus="Blob to data url"
+ We need to revoke them if care about memory.
@@ -166,8 +166,8 @@ We can create a `Blob` of an image, an image part, or even make a page screensho
Image operations are done via `