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Some points about Web Browser


As all of us aware of the term “Web Browser”. Web Browser is the most widely used software. Web Browser is an application porgram which we used to access the internet.

There are many types of web browsers. Some most commonly used web browsers are-
FireFox, Google Chrome, IE , Opera, Safari.

In this post I will tell you some internal of web browsers , like what is the main component of browsers and How they works?

As we know that browser shows web page. Web pages are either html source file or html rendered page on browser.

Components of Web Broewser:
Browsers have many components but here I will tell you some important components of browser.





  • HTML parser
  • JavaScript Engine/Interpreter
  • Rendering Engine


HTML parser Html parser parse the html document and create the DOM(Document Object Model) tree.

Rendering Engine: The main responsbility of this engine to display the content whic is requested by the user.

By default this engine can display HTML , XML and images. This can also shows the other type of document like PDf using Browser plugin. Rendering engine uses html parser to create DOM tree from html.

Rendering starts working after getting the requested content from the networking layer. The basic flow of rendering engine something like this






Firstly it parse the HTML to crete DOM and also parse the external css nad inline css of the document. The combination of styling information with the visual information is used to create the render tree.

Types of Rendering Engine: There are more than one type of rendering engine. Different browser uses differnt rendering engine. This the reason same web page look different in differnt browser. 

 

Points to Remember about xml

Important points concerning xml.

1. First line of xml document should be
   <?xml version="1.0" encoding="utf-8" ?> this is the xml declaration known as "prolog" This shows  the version and encoding about xml document.

2. xml document must have root element, and all other node are child element.

    <employee>
      <emp1>xyz</emp1>
      <emp1>abc</emp1>
   </employee>

3. All xml elements must have closing tag.

    <emp1>xyz</emp1>
    </ > referred to as closing tag

4. xml tags(opening and closing tag) are case sensitive

    <emp1>xyz</Emp> incorrect
    <emp1>xyz</emp1> correct

5. xml attribute value must be quoted

    <emp1 id="101">xyz</emp1> right
    <emp1 id=101>xyz</emp1> wrong.
6. xml have not any predefined tag. user define our own tag.

7. xml elements must be properly nested

8. white space is preserved in xml

9. meta-characters(special characters in xml) in xml

    <, > , </

 do not use these character directly in your xml document because these character
 are the meta-character for xml.

use these &lt; , &gt; instead of <, >

10. xml can be used to store data

11. xml can be used to exchange data

12. Comments in xml

<!-- This is comment -->