What your web browser allows you to check. Internet connection and Internet knowledge. Status of rules in order of priority
I contact all readers of my blog with Roman Chueshov. It’s already too easy for people to go as far as they can, without worrying at all about the programs that stink of profiting from it. Do you know what an Internet browser is and how it works? It’s all about today. I recommend reading this article to the end, where I will explain why it is important to install a number of browsers on your computer and set them up correctly. Come on, go ahead.
Web Browser as it is
I'll start getting familiar with the browser first.
A web browser (another name) is a special program that allows you to view the placement of websites and the information contained on them.
It works like this:
- the program forces http-request to remove information;
- the server grants access;
- the program collects data from established standards;
- The interpreted image code appears on the screen.
Browsers appeared as soon as the Internet was discovered and gradually filled all electronic devices. Today, one of the web browsers will be installed on your computer, tablet or smartphone.
History of creation Web Browser
The largest Web Browser that has a graphical interface, becoming . But after the developers of this company moved to Netscape and began developing a new product, the Mosaic development was launched. Luckily, the output code got into the hands of Microsoft. As a result, the world-famous Vidomy was born Internet Explorer.
There are a lot of people here who can cry out in shock: why is it that IE itself has become so popular, but who hasn’t heard a lot about Mosaic? On the right, Microsoft made one very important and, as it turned out, very smart move - it included the browser as a mandatory update for the operating system (at that time it was Windows 95). Well, the koristuvachs simply ran out of choices - the stench was koristuvachi itself IE.
Internet Explorer Having quickly conquered the market (95% - practically the whole world), and the Netscape robot was finished. In this case, the developers, having closed the project, published the incomplete code under a free license, so that in the future they could use it for the creation.
In 1995, a child was also born Opera. These two glances began to quickly develop, in order to slightly double the market that they were successfully exploiting. And while Microsoft did not act (really, is it possible to get rich, since you are a monopoly?!), Masila and Opera began to become popular. The real battle for the goods has begun, as the market has pushed up to the creation of a new product - .
Suchasni Web Browser
Once you are familiar with the concepts of the Web Browser, you can proceed to selecting programs so that you are satisfied with everything. A few more have already been lost - most of them are still afloat.
Well, the most popular ones are:
- Opera;
- Internet Explorer;
- Apple Safari;
- Yandex browser.
Google Chrome is currently the most powerful browser. These products are based on Chromium and run on the WebKit engine. For a small amount of time, we can win 25% of the market.
And having gained value for the simplicity, functionality and flexibility of the pages, as well as the visibility of a variety of extensions. It is significant that Yandex, being the main competitor of Google, recently presented its version of the program. Pitannya, why would the koristuvachs want to seduce you? I think so, I want it.)
Mozilla Firefox is popular in Russia, as well as Germany and Poland. However, it gradually loses its position and can soon reach the level of Opera. As for the rest, vikorystov became important for mobile devices, and immediately sunk into oblivion. Those same ones come from IE, which struggles at the edges of isolated episodes.
Okremo varto guess about Safari, which was created specifically for Apple products. Enter the list of installed programs on Mac OS X and iOS.
And the Phoenix and Amigo axis are browsers that the koristuvachs have come up with quite a bit. The smells are cost-free and are installed automatically when you visit certain sites. It’s better to guess the virus that you want to remove from your computer as soon as possible.
Remember, if you happen to work with websites, it is very important to remember how to properly display a web resource in your browser. Because We are busy with the layout of the site, then. recreate the layout of the blog in Photoshop, using tags, on the visual appearance in the browser.
Today's users use different browsers, but the display of information (website) is even more important for them.
I have all the latest browsers installed on my computer: Google Chrome, Mozilla Firefox, Opera, Internet Explorer, Apple Safari for Windows, Yandex Browser. You can attract them without any costs on the Internet on official websites.
So that's it for now. Install your browsers on your PC and read the articles from this section, and you will learn how to properly configure them for smooth and uninterrupted work.
With respect, Roman Chueshov
Good afternoon, fellow readers of the Start-Luck blog. Some ideas of simple nutrition can reveal strange speeches that people have never heard of before. We just called to rustle with a light bulb, a micro-haired bird and a saw sucker.
I would like to see an article about how machines work and how to reach a new level. As soon as you can work as a human being, you will soon end up working as a nasty electrician or a master of all trades, for whom it is not a problem to be kind.
Today there are a few words about other speeches. Let's talk about browsers and their operating principles. It’s unlikely that if you happen to have a good browser, then after this article you won’t run out of power due to the influence of sites. Whom I have no doubt about.
Yak vlashovany website
Any electronic resource means a collection of files. Some represent the design, others – the test warehouse. Please write for additional special programming. Not all website creators understand code, but they use simple programs that themselves transform actions into code and files.
If you look at the site as it is viewed by browsers, you will create a folder with an obscure name in which other files will be located. If you look at one of them, you won’t understand anything at all.
This set of documents is located on the publisher’s computer and is not accessible to readers. The stink is not on the Internet. Open the site for public viewing to help. Roughly speaking, they have something similar to large flash drives on which folders with websites are stored.
Each folder is assigned a URL, or, simply put, an address. Enter it into the address bar of your browser and it will kindly lead you to the folder. That’s not all there is to stopping browsers, but we’ll talk about that in the next section.
Browser mission
As I have already said, there are songs with programs that help the mercenaries. And these are browsers that are needed in order to view the site without knowing the code itself, not just by looking at the folder, but in a whole new way.
For example, the programmer says: “The axis of the article, and having clicked on this phrase, the person must move to another side of my site.” Enter the song code here. Don’t worry about it, the browser doesn’t mind and the reader immediately sees it as simple as sending messages from your chairs.
Learning how to program is not as easy as you might think at first glance. There are a lot of simple ones that allow you to simplify your life and work on the Internet. No less cursives that help teapots to master the subtleties of mastery. For example, " WordPress 4: practice creating a website "Mikhaila Rusakova. The lessons are even simpler. For example, skin care can be used as a reference website.
Well, why do we need browsers, we got along with you. Now let's marvel at the stench there is.
Classification
As they say, it’s hard to separate browsers. Not to you who are being deceived - the stench is almost all the same. The difference lies mainly in the interface, but in the simplicity and insignificant nuances.
Today I have already tried this topic more than once: Google Chrome, Yandex Browser, Opera, Mozilla. I can’t imagine dividing them up in this way.
I'll give you a simple alternative. When it comes to cowbass, it can be classified by stock, price, method of preparation (smoked, boiled). There are not so many browsers and all of them are approximately the same, so they can be divided only by the browser, but, as for me, this is a lousy classification.
Their principle of work and mission is the same regardless of the situation. So how do people rob browsers? What matters is the interface. All small hustle-bustles are hovering and the people's voice is calling to them. For example, when you log into Yandex Browser, you will be encouraged to read new products that may be useful to you. This is what the koristuvachs are drinking.
It seems that the Google Chrome browser opens swidden websites. I can’t say how much of this is true. I am especially interested in a number of browsers, and the ability of everyone to hide on the Internet. Let Yandex confirm about turbo modes, but if in the evening the network has been re-engineered and the torrent is running completely, you won’t be able to download the page in a second.
How to choose a browser, install a browser and just wonder which one you find most useful. Well, that's all. Also subscribe to the newsletter to receive clear information.
Until new challenges and good luck.
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Peredmova
This report reveals the internal workings of the WebKit and Gecko systems and is the result of extensive research conducted by Israeli web programmer Talia Garciel. She has spent many years collecting all the information that is published about connected browsers (div. section) and has devoted many hours to analyzing their output code. What did Tali herself write:
If 90% of computers had IE installed, you had to put up with this, which is the mystery of the “black screen”, but now, if more than half of the computer users choose browsers with open source code, the time has come to get back, what they have in common i, in millions rows of program code in C++...Tali published the results of the investigation on her website, but we respect that they deserve the respect of a wider audience, so we place them here with some conciseness.
A web browser that is familiar with the internal mechanics of how browsers work makes better decisions when choosing one or the other. In order to complete this voluminous document, we recommend that you read it as it is very important and we guarantee that you will not be harmed by it. Paul Irish, Chrome Developer Relations
Enter
Web browsers may be the most advanced programs. To whose assistant I will explain how to deal with stinks. Let us take a closer look at what you expect the moment you type google.ru in the address bar until the Google page appears on the screen.
Let's look at what browsers we have
Today there are five major browsers: Internet Explorer, Firefox, Safari, Chrome and Opera. For example, browsers with closed code are used: Firefox, Chrome and Safari (the code is often hidden). Based on the statistics of the popularity of browsers on the StatCounter website, as of the beginning of 2011, Firefox, Safari and Chrome browsers were installed on 60% of devices in total. Thus, browsers with open source code are in even stronger positions today.
Basic browser functions
The main purpose of the browser is to display web resources. For this purpose, a query is sent to the server, and the result is displayed in the browser window. The resources are mainly HTML documents, but they can also include a PDF file, an image, or some other location. The extension of a resource is indicated by an additional URI (unified resource identifier).
The way the browser processes and displays HTML files is determined by the HTML and CSS specifications. The stinks are being broken up by the Consortium W3C which promotes standards for the Internet.
Many modern browsers have provided only a few specifications, and they have been created along with extensions. For web developers, this meant serious problems and madness. Today, most browsers meet all specifications to a greater or lesser extent.
The user interfaces of various browsers can be quite complex. The main elements of the browser interface are listed below.
- Address bar for entering URI
- Navigation buttons "Back" and "Forward"
- Bookmarks
- Buttons for updating and updating the page
- Button "Dome" to go to the main page
It’s not surprising that there are no specifications that would define standards for the browser interface. Today's interfaces are the result of a vast evolution, and it is known that developers often copy one another. The HTML5 specification does not specify what the browser interface can do, as long as the basic elements are listed. The address row, the row and the toolbar will appear before them. Of course, there are also specific functions, such as the Firefox attraction manager.
Structure of the upper level
Below are the main components of the browser ().
- Koristuvalnytskyi interface– includes the address row, the “Back” and “Forward” buttons, the bookmarks menu, etc. Until then, all elements are shown, except for the window in which the active page is displayed.
- Browser Engine– interacts with the interface of the imaging module.
- Imaging module- Indicates that the powered area is displayed on the screen. For example, when an HTML document is loaded, the rendering module parses the HTML and CSS code and displays the result on the screen.
- Merege components– suitable for creating edge calls such as HTTP requests. Its interface does not depend on the type of platform, for which there is a different implementation.
- Vikonavcha part of the koristuvach interface– Used to display basic widgets, such as windows and fields with lists. This universal interface also depends on the platform type. The last part always introduces methods to the interface of a particular operating system.
- JavaScript interpreter– is used for syntactic analysis and analysis of JavaScript code.
- Bunch of tributes- Necessary for saving processes. The browser saves various types of data to your hard drive, such as cookies. The new HTML specification (HTML5) has a special term “database”: a full-fledged (albeit lighter) browser-based database.
Please note that Chrome, unlike most browsers, maintains a number of instances of the display module, one per tab, as well as adjacent processes.
Imaging module
As you can guess from the name, the display module is responsible for displaying the powered area on the browser screen.
You are required to display HTML and XML documents, as well as images. Special modules (browser extensions) that are connected can be displayed in other places, such as PDF files. However, this section covers the main functions: rendering HTML documents and images formatted using CSS styles.
Imaging modules
Browsers (Firefox, Chrome and Safari), to tell us, have two display modules. Firefox is stagnant with Gecko - the Mozilla version is free, and Safari and Chrome are victorious with WebKit.
WebKit is a rendering module with open source code, which has been developed for the Linux platform and adaptations by Apple for Mac OS and Windows. Detailed information can be found on the website webkit.org.
Basic robot scheme
The imaging module replaces the received document with the intermediary protocol, called fragments of 8 KB.
The diagram of further operation of the imaging module appears below.
Malyunok. Scheme of the robotic imaging module.The rendering module parses the HTML document and translates tags from nodes in the tree. Information about styles comes from both external CSS files and style elements. This information and instructions for displaying in HTML files are used to create another tree - .
It is important to combine orthocutaneous plants with visual attributes, such as color and size. The straight cutters are located in the order in which the stinks appear on the screen.
After the creation of the image tree, elements begin, at each skin node the coordinates of a point on the screen are given, and they may appear. Then it shows which nodes of the display tree are successively drawn behind the help of the computer interface of the user.
It is important to understand that this is a sequential process. For the user's convenience, the display module can display the changes on the screen as soon as possible, so the creation of the display tree and layout can be printed even before the parsing of the HTML code is completed. Some parts of the document are analyzed and displayed on the screen, while others are not transmitted through the network.
Use it robotically
Malyunok. Schematic diagram of the WebKit display module. Malyunok. Schematic diagram of the Mozilla Gecko() imaging module.As can be seen from Little Ones 3 and 4, WebKit and Gecko differ in terminology, but their work schemes are practically identical.
In Gecko, the tree of visually formatted elements is called a frame tree, in which a skin element is a frame. WebKit creates a render tree, which is made up of render objects. The placement of elements in WebKit is called layout or layout, and in Gecko it is called reflow. The combination of DOM nodes and visual attributes to create a view tree is called an attachment in WebKit. The small power of Gecko, which does not bother with semantics, is due to the fact that there is another layer between the HTML file and the DOM tree. This is called a content sink and serves as a mold for DOM elements. Now let's talk about the skin stage of the report.
Syntactic analysis: hidden pages
Some parsing is an important stage of the module, which we will look at in this report. Let’s talk about it in a short introduction.
During the syntactic analysis of a document, attention is paid to its transformation into a readable and literal structure. The result of syntactic analysis is usually a tree of nodes, which forms the structure of the document. It is called a syntactic analysis tree, or simply a syntactic tree.
For example, as a result of parsing the expression 2 + 3 - 1, the following tree can be obtained:
Malyunok. Wood vuzol for mathematical expressions.Grammar
Syntactic analysis is performed on the basis of written rules, which are indicated by the format of the document. For each format, there are grammatical rules that arise from the vocabulary and syntax. The stench is created t.z. . Natural languages do not follow the rules of context-free grammar, so standard syntactic analysis techniques are suitable for them.
Syntactic and lexical analyzer
At the same time, lexical analysis comes to a standstill with syntactic ones.
Lexical analysis includes information on tokens and lexemes. Tokens create a vocabulary of both other languages and constructive elements for creating documents. In natural language, all the words that can be found in dictionaries were tokens.
The sense of syntactic analysis lies in the stagnant syntactic rules of the language.
Document analysis consists of two components: lexical analyzer, which parses the input sequence of characters on active tokens, and parser, which analyze the structure of a document based on the syntactic rules of a given language and form a syntactic tree. The analyzer ignores non-informative symbols, such as gaps and row transfers.
Malyunok. Transition from the output document to the syntax tree.Syntactic analysis is an iterative process. The parser then requests a new token from the lexer and checks its consistency with the syntax rules. When it is possible to establish a type, a new node is created for the token in the syntax tree, and the analyzer consumes the new token.
As soon as a token matches a given rule, the parser encloses it and queries such tokens. This will continue until a rule is found to match all token deposits. If you don't know this rule, the analyzer makes mistakes. This means that the document contains syntactic corrections and cannot be processed in any way.
Translation
The syntax tree is not always the residual result. Parsing is often used in the process of translating the input document into the required format. The butt can be a compilation. The compiler, which translates the output code into machine code, first parses it and forms a syntax tree, and then creates a document with machine code based on this tree.
Malyunok. Stages of compilation.An example of syntactic analysis
Little 5 shows a syntactic tree inspired by the mathematical formula. It is important to understand the elementary mathematical language and take a look at the process of syntactic analysis.
Vocabulary: our language can include whole numbers, plus and minus signs.
Syntax
- The structural elements of a language are language, operands and operators.
- Language can take revenge on any number of viruses.
- Viraz is a sequence that consists of an operand, an operator, and another operand.
- Operator - ce token plus or minus.
- The operand is the token of the integer chi viraz.
Let's look at the input sequence of symbols 2+3 – 1.
The first element that confirms the rule is 2 (together with rule No. 5, this is the operand). Another such element is 2 + 3 (the sequence that is added to the operand, operator and another operand is determined by rule No. 3). Let’s start with the following principles: the sequence 2 + 3 – 1 is equal to the following. The fragments 2+3 are an operand, and we extract the sequence that is the sum of the operand, the operator, and another operand, which indicates the corresponding expression. Row 2 + + does not correspond to the rules, so it would be considered invalid.
The formal meaning of the vocabulary and syntax
The language in the butt can be translated as follows:
INTEGER:0|* PLUS: + MINUS: - As you know, the whole numbers are calculated using regular expression.
The syntax is primarily described in the BNF format. Language in general can be described as follows:
Expression:= term operation term operation:= PLUS | MINUS term:= INTEGER | expression
As was previously stated, language can be parsed using standard parsers, such as a grammar contextless This can be fully expressed in the BNF format. The formal definition of context-free grammar can be found in the Wikipedia article.
Types of parsers
There are two types of parsers: low-end and high-end. The first analysis will burn to the bottom, and the others will burn to the bottom. Downstream analyzers parse the structure of the top level and look for similar syntactic rules. The input analyzers initially analyze the input sequence of symbols and step by step identify its syntactic rules, starting with the rules of the lower level and ending with the rules of the upper level.
Now it’s amazing how these two types of analyzers resisted our butt.
A similar analyzer started from the rules of the upper level and found that 2 + 3 is equal. Then we find out that 2 + 3 – 1 is also a virus (in the process of different expressions there are similarities with other rules, which have always been considered the rule of the upper level).
The output analyzer has processed the sequence of symbols, found a suitable rule that can replace the fragment of the expression, and so the remaining sequence. Viruses with a partial appearance are then placed on the analyzer stack.
When running such an analyzer, the input sequence of symbols is collapsed to the right (imagine a cursor that is placed on the beginning of the sequence and during the analysis is collapsed to the right) and is gradually reduced to syntactic rules.Automatic creation of parsers
There are special programs for creating parsers, called generators. It is enough to add language grammar (vocabulary and syntactic rules) into the generator, and it will automatically create an analyzer. To create a parser, you need a deep understanding of the principles of its work, and it is not so easy to create it manually, so the generators can be very crude.
DOM
The syntax tree consists of DOM elements and attribute nodes. DOM – Document Object Model – serves to represent an HTML document and the HTML element interface to external objects such as JavaScript.
At the root of the tree there is a Document object.
The DOM is practically identical to layout. Let's take a look at the butt of the marking:
Hello World
Under the words “a tree to place DOM nodes” it means that the tree is made up of elements that implement one of the DOM interfaces. Browsers have specific implementations that provide additional attributes for internal wikis.
Parsing algorithm
As has already been said in the previous sections, parsing HTML code cannot be done using standard downstream or outbound parsers.
Below is the reason given.
- The language has a “merciful” character.
- Browsers have built-in mechanisms for processing certain parts of the HTML code.
- The parse cycle is characterized by the possibility of re-entry. The output document does not change during the analysis process, however, when entering HTML tags into the script that replace document.write, new tokens can be added, so the output code can be changed.
Some standard parsers are not suitable for HTML; browsers create different parsers.
An algorithm for syntactic analysis of report descriptions in the HTML5 specification. It consists of two stages: lexical analysis and wood analysis.
As a result of lexical analysis, the input sequence of symbols is divided into tokens. HTML tokens are preceded by opening and closing tags, as well as the names and values of attributes.
The lexical analyzer identifies a token, passes it to the tree constructor and proceeds to the next symbol, searching for further tokens, and so on until the end of the input sequence.
Malyunok. Stages of parsing HTML code (Dzherelo: HTML5 specification).Lexical analysis algorithm
The result of the algorithm is an HTML token. The algorithm of expressions is like an automaton with a terminal number of turns. The skin site produces one or more symbols of the input sequence, on the basis of which such a site is determined. It must be kept at the stage of lexical analysis and the stage of tree shaping, so that the processing of one and the same symbol can lead to different results (different stages) in the production line. The algorithm is simple, so that we can clearly describe it here, so let’s take a look at the example, which will help us better understand the principle of our work.
Vikonaemo lexical analysis of simple HTML code:
Hello world
Cob camp - "tribute". When the analyzer displays the symbol< , состояние меняется на "hide tag". As soon as the letter (a-z) appears, the token of the tag that opens is created and changes to "tag name". It will be saved until the > symbol is displayed. The symbols are added one by one to the name of the new token. Our vipad shows the html token.
When the symbol > is displayed, the token is ready and the analyzer turns around "tribute". Tag
it just turns out that way. Thus, the analyzer has already generated the html and body tags and turned to "tribute". The appearance of the letter H in the phrase Hello world leads to the generation of a token for the symbol. The same is repeated with other letters until the analyzer reaches the symbol< в теге . A token is created for the skin symbol of the phrase Hello world.Then the analyzer turns around again "hide tag". Revealing to the symbol / leading to the creation of the token of the tag that closes, and transition to the state "tag name". It will be saved until the > symbol is displayed. At this point, a token for a new tag is generated, and the analyzer turns back to "tribute". Sequence of characters