{"id":41868,"date":"2023-01-31T10:00:44","date_gmt":"2023-01-31T04:30:44","guid":{"rendered":"https:\/\/www.aplustopper.com\/?p=41868"},"modified":"2023-02-01T09:16:16","modified_gmt":"2023-02-01T03:46:16","slug":"plus-two-computer-science-notes-chapter-4","status":"publish","type":"post","link":"https:\/\/www.aplustopper.com\/plus-two-computer-science-notes-chapter-4\/","title":{"rendered":"Plus Two Computer Science Notes Chapter 4 Web Technology"},"content":{"rendered":"
Communication On The Web<\/strong><\/p>\n Following are the steps happened in between user’s \u2019 click and the page being displayed<\/p>\n Client to web server communication<\/span><\/p>\n This communication is earned out between client to the web server (shopping site). The technology used to protect data that are transferred from client to web server is HTTPS (HyperText Transfer Protocol Secure). This encrypts user name, password etc. and sent to the server. HTTPS works using Secure Sockets Layer (SSL) ensures privacy as well as prevents it from unauthorised access (changes) from other web sites.<\/p>\n Following are the steps ,<\/p>\n Web server to web server communication<\/span><\/p>\n This communication is usually carried out between web server (seller) to another web server (normally bank). Forthe safe transactions Digital certificate issued by third party web sites are used.<\/p>\n Payment gateway is a server (Computer) that acts as a bridge (interface) between merchant\u2019s server and bank’s serverto transfer money.<\/p>\n Web Server Technologies<\/strong><\/p>\n Webserver<\/span><\/p>\n A computer with high storage capacity, high speed and processing capabilities is called a web server.<\/p>\n Software ports<\/span><\/p>\n The computer is not a single unit. It consists of many components. The components are connected to the computer through various ports. Two types of ports Hardware and Software. Software ports: It is used to connect client computers to the server to access different types of services. For example HTTP, FTP, SMTP etc. Unique numbers are assigned to software ports to identify them. It is a 16 bit number followed by IP address.<\/p>\n DNS servers<\/span><\/p>\n A DNS server is a powerful computer with networking software. It consists of domain names and their corresponding IP addresses. A string address is used to represent a website, it is familiar to the humans. The string address is mapped back to the numeric address using a Domain Name System (DNS). It may consists of 3 or 4 parts. The first part is www., the second part is website name, the third top level domain and the fourth geographical top level domain. .<\/p>\n eg-http:\/\/wwwsiic.kerala.gov.in \/ results.html.<\/p>\n http<\/span>:- http means hyper text transfer protocol. It is a protocol used to transfer hypertext,<\/p>\n www<\/span>:- World Wide Web. With an email address we can open our mail box from anywhere in the world, nic.kerala It is a unique name. It is the official website name of National Informatic Centre,<\/p>\n gov<\/span>:- It is the top level domain. It means that it is a government organisation\u2019s website,<\/p>\n in<\/span>:- It is the geographical top level domain. It represents the country, in is used for India. results.htmlIt represents the file name.<\/p>\n Web Designing<\/span><\/p>\n Any text editor can be used for web designing. Besides that many software tools are available in the market to make the web pages more attractive and interactive, some of the popular softwares are Adobe dream weaver, Microsoft Expression web, Blue fish, Bootstrap etc.<\/p>\n Static And Dynamic Web Pages<\/strong><\/p>\n Some pages are displaying same content(same text, images,etc) every time. Its content are not changing. This type of web pages are called static page. Conventional wep pages display static pages and has some limitations.<\/p>\n Advanced tools are used to create web pages dynamic, that means pages are more attractive and interactive. For this JavaScript, VBScript, ASP, JSP, PHP, etc are used.<\/p>\n Following are the differences<\/p>\n Scripts<\/strong><\/p>\n Scripts are small programs embedded in the HTML pages. The attributes used are<\/p>\n Two types of scripts 2. Server scripts – These are scripts executed by the server. Scripting Languages<\/span><\/p>\n a. JavaScript: Java script(developed by Brendan Eich for the Netscape browser) is a platform \/ncfepencfentscripting language. Means It does not require a particular browser. That is it runs on any browser hence it is mostly accepted scripting language.<\/p>\n Ajax : It is a technology to take data from the server and filled in the text boxes without refreshing (without reloading the entire page) the web page. Ajax is Asynchronous JavaScript and Extensible Mark up Language (XML). XML is an Extensible Mark up Language, it allows to create our own new tags. This technology uses JavaScript to perform this function. When we turned off JavaScript features in the browser, the Ajax application will not work.<\/p>\n b. VB Script: VB Script(developed by Microsoft) is a platform dependent scripting language. Means it requires a particular browser(MS Internet Explorer) to work that is why it is not widely accepted scripting language.<\/p>\n c. PHP (PHP Hypertext Preprocessor)<\/p>\n d. Active Server Pages (ASP)<\/p>\n e. Java Server Pages (JSP)<\/p>\n Cascading Style Sheet (Css)<\/strong><\/p>\n It is a style sheet language used for specifying common format like colour of the text, font, size, etc. other than the HML codes. That is CSS file used to separate HTML content from its style.<\/p>\n It can be written in 3 ways as follows<\/p>\n Code reusability(just like a function in C++) is the main advantage of CSS and can be used in all the pages in a website<\/p>\n Attributes of <HTML> tag<\/span><\/p>\n 1. Dir- This attribute specifies the direction of text displayed on the webpage, values are ltr(left to right), rtl(right to left) Attributes of <MARQUEE><\/span><\/p>\n Attributes<\/span><\/p>\n Special Characters<\/span><\/p>\n\n
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\nHardware ports : Monitors are connected through VGA ports and the keyboard or mouse are connected through PS\/2 ports.<\/p>\n\n\n
\n Default Port No.<\/td>\n Services<\/td>\n<\/tr>\n \n 20 & 21
\n22
\n25
\n53
\n80
\n110
\n443<\/td>\nFile Transfer Protocol (FTP)
\nSecure shell (SSH)
\nSimple Mail Transfer Protocol (SMTP)
\nDomain Name System (DNS)
\nservice Hypertext Transfer Protocol (HTTP)
\nPost Office Protocol (POP3)
\nHTTP Secure (HTTPS)<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n\n\n
\n Static web pages<\/td>\n Dynamic web pages<\/td>\n<\/tr>\n \n Content and layout is fixed<\/td>\n Content and layout is changed frequently<\/td>\n<\/tr>\n \n Never use database<\/td>\n Database is used<\/td>\n<\/tr>\n \n Run by browser<\/td>\n It runs on the server and the result get back to the client(browser)<\/td>\n<\/tr>\n \n Easy to develop<\/td>\n Not at all easy<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n
\n<SCRIPT> tag is used to write scripts<\/p>\n\n
\n1. Client scripts – These are scripts executed by the browser.
\nEg: VB Script, Javascript etc.<\/p>\n
\nEg: ASP, JSP, PHP, Perl, etc.<\/p>\n\n
\n
\n
\n
\n
\n
\n<HTML>
\n<HEAD>
\n<TITLE>
\ngive title to the web page here
\n<\/TITLE>
\n<\/HEAD>
\n<BODY>
\nThis is the body section.
\n<\/BODY>
\n<\/HTML><\/li>\n
\nEg: empty tag:- <hr>, <br> etc., container tag:- <html>, <\/html>, etc.<\/li>\n
\n2.. Lang- This attribute specifies the language values areEn(English), Hi(Hfndi), Ar(Arabic),etc Eg: <HTML dir=\u201dltr\u201d lang=\u201dHi\u201d><\/p>\n\n
\n<H1 >,<H2>,<H3>,<H4>,<H5> and <H6>.
\n<H1> provides big heading and <H6> provides smallest.<\/li>\n
\nIt is used to give indentation(giving leading space to a line)<\/li>\n\n
\n<marquee behavioF”slide” scrollamount-‘100H> hello<\/marquee>
\n<marquee behavior=”attemate” scrollamount= “100”>hello<\/marquee><\/li>\n\n