Computer Science:JavaScript
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This document discusses JavaScript, its history, uses, and features. It provides an introduction to JavaScript, noting that it is a lightweight programming language used to make web pages interactive by inserting dynamic text, reacting to events, getting information about the user's computer, and performing calculations. The document discusses how JavaScript was created by Brendan Eich at Netscape in 1995 and how it enhances the user experience on web pages by creating responsive and interactive elements. It also compares JavaScript to Java and outlines different types of pop-up boxes that can be used in JavaScript like alert, confirm, and prompt boxes.
Computer Science:JavaScript
- 1. JavaScript Aparna U Assistant Professor Department of Vocational Studies St. Mary’s College, Thrissur
- 2. JavaScript,Aparna U,St.Mary’s College JAVASCRIPT: Introduction A lightweight programming language ("scripting language") It is used to make web pages interactive Insert dynamic text into HTML (ex: user name) React to events (ex: page load user click) Get information about a user's computer (ex: browser type) Perform calculations on user's computer (ex: form validation)
- 3. JavaScript,Aparna U,St.Mary’s College Brendan Eich(1995) NetScape recruited Brendan Eich with the goal of Scheme Programming Language into its NetScape Navigator
- 4. JavaScript,Aparna U,St.Mary’s College Benefits of JavaScript To put things simply, JavaScript is an object orient programming language designed to make web development easier and more attractive. JavaScript is used to create responsive, interactive elements for web pages, enhancing the user experience. It can modify a page without having to post back to the server (faster UI) It can make small, quick changes to page without waiting It can respond to user actions like clicks and key presses
- 5. JavaScript,Aparna U,St.Mar’ys College Why JS? The importance of JavaScript as a web technology can be determined from the fact that it is currently used by 94.5% of all websites. As a client-side programming language, JavaScript helps web developers to make web pages dynamic and interactive by implementing custom client-side scripts.
- 6. JavaScript,Aparna U,St.Mary’s College Do Java and JavaSript Differ? Java is an OOP programming language while Java Script is an OOP scripting language. Java creates applications that run in a virtual machine or browser while JavaScript code is run on a browser only. Java code needs to be compiled while JavaScript code are all in text.
- 7. JavaScript,Aparna U,St.Mar’ys College JS POP-UP BOXES There are three different Pop up boxes in JS Alert Boxes Confirm Boxes Prompt Boxes
- 8. JavaScript,Aparna U,St.Mary’s College An alert box is often used if you want to make sure information comes through to the user. When an alert box pops up, the user will have to click "OK" to proceed. Here is the simple example to display a text in alert box <script type”text/javascript”> alert(“This is an alertbox”); </script> Alert Box
- 9. JavaScript,Aparna U,St.Mar’ys College A confirm box is often used if you want the user to verify or accept something When a confirm box pops up, the user will have to click either "OK" or "Cancel" to proceed. Here is the example for confirm box. <script type="text/javascript"> mess1='Press Ok to Continue.'; x = confirm(mess1); if (x == true){ alert("You have clicked on Ok Button.");} else{ alert("You have clicked on Cancel Button."); } </script> Confirm Box
- 10. JavaScript,Aparna U,St.Mar’ys College A prompt box is often used if you want the user to input a value before entering a page. When a prompt box pops up, the user will have to click either "OK" or "Cancel" to proceed after entering an input value. If the user clicks "OK“, the box returns the input value. If the user clicks "Cancel“, the box returns null. Here is the example for prompt box. <script> var person = prompt("Please enter your name", "Harry Potter"); if (person == null || person == "") { txt = "User cancelled the prompt."; } else { txt = "Hello " + person + "! How are you today?";} </script> Prompt Box