Event Handling in JS

Duration: 5 min

This video lesson is available to enrolled students.

Return to /learn/RSSB-INFORMATICS-ASSISTANT/internet-web-technology/server-side-security/server-side-scripting/asset-event-handling-in-js after enrolling

Inside: a video lesson and guided study material.

Module outline

  1. Numerical Ability & Problem Solving: Speed Mathematics and Basic Mathematics, Arithmetic, Number System, HCF LCM, Divisibility Rules, Percentage, Ratio and Proportion (Ratios), Average, Profit and Loss, Simple Interest and Compound Interest, Mixture and Alligation, Time and Work, Pipe and Cistern, Speed Time and Distance, Age Problems, Partnership, Data Interpretation, Mental Ability, Sequence and Series (Series), Powers and Exponents (Surds and Indices), Algebra, Statistics, Logarithm, Mensuration and Geometry, Permutation and Combination, Probability, Sequences and Series, Powers, Surds and Logarithms, Subject-Verb Agreement, Sentence Completion, Geometry, Sentence Structure and Correction, Data Sufficiency, Trigonometry, Measurement and Quantity Take-Off, Signal Space and Optimum Detection, Probability, Statistics, Algebra, Time and Work, Speed, Time and Distance, Data Interpretation, Combinatorics
  2. Logical Reasoning: Series (Number and Letter Series) (Numerical Relations and Reasoning), Coding Decoding, Data Sufficiency, Syllogisms, Deductive and Inductive Reasoning (Logical Deduction and Induction) (Prepositional Reasoning), Seating Arrangements, Blood Relations, Directions (Direction Test), Non Verbal Reasoning (Spatial Aptitude) (Spatial Reasoning) (Visual Reasoning), Analytical Reasoning (Counting Figures Reasoning), Puzzle Solving (Puzzles), Calendar, Clock, Cubes & Dices, Logical Sequence Of Words, Venn Diagram, Data Arrangement, Inequality, Analogy, Ranking, Order and Sequence, Selection Decision Table (Decision Making), Alphabet and Word Tests, Numerical Reasoning, Number System, Averages, Mixtures and Alligation, Percentages, Series Completion, Analogy and Classification, Patterns in Two-Dimensional Figures, Coding and Decoding, Mathematical Operations, Direction Sense, Logical Deduction and Induction, Syllogisms and Venn Diagrams, Critical Reasoning, Order, Ranking and Sequence, Reading Comprehension, Profit, Loss and Discount, Constraint Puzzles, Traverse Surveying, Ratio and Proportion, Mensuration, Permutations and Combinations, Clocks and Calendars, Assembling and Grouping of Shapes, Transformation of Shapes, Three-Dimensional Patterns and Visualization, Cubes and Dice, Vocabulary, Blood Relations
  3. General Knowledge & Current Affairs (India + Rajasthan): History, Geography, Polity, Indian Economy, Static General Knowledge, State Wise GK, GK- Current Affairs, Environment, Physics
  4. Computer Fundamentals & Operating Systems: Basics of COA, Floating Point Rep, Digital Systems & Boolean Basics, Number Representation, Number System, Introduction to OS, File Management, Windows OS, Unix OS, Linux OS, Register Transfer and Microoperations, Virtual Memory
  5. Computer Networks: Introduction to CN, Data Communication, DLL: Error Control, DLL: Access Control, Data Link Layer - Ethernet, Net Layer: IPv4 & Proto, Application Layer, Hardware Basics, Network Security
  6. Cyber Security: Cyber Threats and Malware Attacks, Role of Internet and Web Services, Security in Mobile and Wireless Computing, Electronic Data Interchange and E-Commerce, Physical Security and Cryptography Basics, Intrusion Detection Systems (IDS), Cyber Safety and Security, Ethical Hacking
  7. Programming (C & OOP): C Fundamentals, Control Flow, Arrays & Pointers, Functions, Storage Classes, Structures & Enums, DMA, Macros, Scoping & File Handling, OOPS with C++, Operators & Expressions, Sorting Algorithms, Java Fundamentals, Java
  8. MS Office & Data Processing: MS Office Applications, Basics of DBMS
  9. Internet & Web Technology: Society, Law & Ethics, Terms & Abbreviations, Keyboard Shortcuts, Emerging Tech Trends, Artificial Intelligence, Emerging Technologies, Internet Fundamentals, Website, Browser & Services, Web Design & Development, Protocols & Services, Web Publishing & Hosting, Server Side & Security
AI summary & chapters

AI Summary

An AI-generated summary of this video lecture.

The lecture introduces event handling in JavaScript, defining it as a software routine that processes actions such as keystrokes and mouse movements. It outlines the functions of event handling, including identifying where an event should be forwarded, making the forward event, and taking appropriate actions like writing to a log or sending an error. The session transitions to a detailed table of specific event handlers. The instructor explains handlers like onAbort, onBlur, onChange, and onClick. Finally, a practical example demonstrates a real-time clock using the onload event handler, showing how JavaScript interacts with HTML forms to update display values dynamically every second.

Chapters

  1. 0:00 – 2:00 00:00-02:00

    The instructor begins by defining event handling as a routine processing user actions. A slide lists functions including identifying where events are forwarded and taking actions like logging errors. The view shifts to a table of event handlers. The instructor highlights onAbort, onBlur, onChange, and onClick, explaining that onClick triggers when a button is clicked or a link is pushed. She also points out onLoad, which executes when a window finishes loading. The table continues with onError, onFocus, onMouseOver, and onMouseOut, providing descriptions for each trigger condition. For instance, onFocus executes when input focus enters a field, while onMouseOver is called when the mouse is placed over a specific link. The instructor systematically goes through the list, ensuring students understand the specific user interaction that activates each handler.

  2. 2:00 – 4:47 02:00-04:47

    The lecture presents a code example titled Simple Program on onload() Event handler. The JavaScript function time() initializes a Date object and extracts hours, minutes, and seconds using methods like getHours() and getMinutes(). The code formats these into a string and assigns it to an input field's value property using document.frmty.timetxt.value=ty. The instructor underlines setInterval("time()", 1000) to explain the 1-second update loop. She draws a browser window diagram to visualize the text box where the time appears, emphasizing the onload="time()" attribute in the body tag which triggers the function upon page load. The HTML structure includes a form named frmty and an input field named timetxt, which are referenced in the JavaScript to update the display.

The lesson effectively bridges theory and practice. It starts with abstract definitions of event handling mechanisms and specific handler names. It culminates in a concrete application where the onload event triggers a script to update a UI element every second, demonstrating the lifecycle of an event from trigger to execution to visual feedback. The code example reinforces the concept of DOM manipulation and timing functions within the context of event-driven programming. By combining the Date object with setInterval, the lecture shows how to create dynamic, real-time updates on a webpage. This practical demonstration solidifies the theoretical concepts presented earlier in the lecture.

Loading lesson…