jQuery MCQs
Q.1 What does the .stopPropagation() method do?
A. Stops the event from bubbling up the event chain
B. Stops all functions
C. Prevents default actions
D. None of the above
Q.2 What method would you use to trigger an event handler of ‘submit’ event programmatically?
A. .trigger(‘submit’)
B. .invoke(‘submit’)
C. .call(‘submit’)
D. .execute(‘submit’)
Q.3 How do you remove an event handler in jQuery?
A. .unbind()
B. .detachEvent()
C. .removeEvent()
D. .off()
Q.4 Which method stops the default action of an event?
A. .stop()
B. .preventDefault()
C. .halt()
D. .stopAction()
Q.5 How do you attach an event handler to elements that may be added dynamically in jQuery?
A. .bind()
B. .on()
C. .live()
D. .delegate()
Q.6 What jQuery method is used to bind a click event to a button?
A. .onClick()
B. .click()
C. .buttonClick()
D. .triggerClick()
Q.7 If $(‘input’).val() returns undefined, what might be the reason?
A. No input elements are present
B. Input is not of type text
C. Input has no value
D. Multiple inputs are present
Q.8 What could cause the selector $(‘#id’) to return more than one element?
A. Invalid HTML structure
B. Multiple elements with the same ID
C. jQuery bug
D. None of these
Q.9 Why might $(‘.class’).hide() not work if the class is correctly specified?
A. Incorrect jQuery version
B. Syntax error in code
C. Class does not exist at runtime
D. jQuery not loaded
Q.10 What jQuery method is used to get the value of an attribute for the first element in the set of matched elements?
A. .getAttr(‘attribute’)
B. .attribute(‘attribute’)
C. .attr(‘attribute’)
D. .value(‘attribute’)
Q.11 How can you add a new class to selected elements in jQuery?
A. .addClass(‘newClass’)
B. .newClass(‘newClass’)
C. .setClass(‘newClass’)
D. .toggleClass(‘newClass’)
Q.12 Which jQuery method removes the selected element from the DOM?
A. .delete()
B. .detach()
C. .remove()
D. .erase()
Q.13 How would you hide all elements with the class “hide-me” using jQuery?
A. .hideClass(‘hide-me’)
B. $(‘.hide-me’).hide()
C. hide(‘.hide-me’)
D. $(‘.hide-me’).remove()
Q.14 What does the selector $(‘li:odd’) select?
A. Every odd li element
B. Every even li element
C. All li elements
D. No li elements
Q.15 How do you select all input elements of type checkbox that are checked?
A. $(‘input[type=”checkbox”]:checked’)
B. $(‘checkbox:checked’)
C. $(‘input:checked’)
D. $(‘input[type=checkbox]’)
Q.16 How can you select elements with an attribute value starting with “https” in jQuery?
A. $(‘[href^=”https”]’)
B. $(‘[href*=”https”]’)
C. $(‘[href$=”https”]’)
D. $(‘a[href^=”https”]’)
Q.17 What is the result of the selector $(‘div:first’)?
A. Selects the first div in the document
B. Selects the first div in each section
C. Selects the first child div
D. Selects none of the above
Q.18 Which jQuery method is used to select elements that are hidden?
A. .hidden()
B. .findHidden()
C. .is(‘:hidden’)
D. $(‘:hidden’)
Q.19 How do you select an element with an ID of “unique” using jQuery?
A. $(‘#unique’)
B. .getId(‘unique’)
C. .$(‘unique’)
D. .querySelector(‘#unique’)
Q.20 Which selector is used to find elements with a specific class in jQuery?
A. .findClass()
B. .class()
C. .$()
D. $(‘.className’)
Q.21 How do you select all <p> elements within a <div> using jQuery?
A. $(‘div p’)
B. $(‘div > p’)
C. $(‘div + p’)
D. $(‘div, p’)
Q.22 A jQuery selector doesn’t return any elements. What could be the most likely cause?
A. Incorrect selector syntax
B. Elements do not exist
C. jQuery not loaded
D. Script error
Q.23 Which jQuery method is used to set the text content of an element?
A. .setText()
B. .text()
C. .textContent()
D. .setContent()
Q.24 vWhat type of files can be manipulated using jQuery?
A. HTML only
B. CSS only
C. JavaScript only
D. HTML, CSS, and JavaScript
Q.25 Which jQuery function is used to select elements by tag name?
A. .getElement()
B. .select()
C. .$()
D. .query()
Q.26 How can jQuery be added to a web page?
A. Link to a local copy
B. Link to a CDN
C. Both
D. Neither
Q.27 Is jQuery a library for client-side or server-side scripting?
A. Client-side
B. Server-side
C. Both
D. None
Q.28 What is jQuery primarily used for?
A. CSS manipulation
B. Server-side operations
C. HTML document manipulation
D. Networking
Q.29 Which jQuery method is used to document-ready event?
A. .onDocumentReady()
B. .ready()
C. .load()
D. .documentReady()
Q.30 What does the $ symbol represent in jQuery?
A. $ represents a library function
B. $ is an alias for jQuery
C. $ is a variable
D. $ is an operator
Q.31 How can you add a CSS class to a set of selected elements in jQuery?
A. .addClass(‘new-class’)
B. .pushClass(‘new-class’)
C. .insertClass(‘new-class’)
D. .applyClass(‘new-class’)
Q.32 How do you attach a ‘click’ event to an element that exists now or in the future?
A. .live(‘click’, function())
B. .bind(‘click’, function())
C. .on(‘click’, function())
D. .attach(‘click’, function())
Q.33 Which method is used to set the HTML content of an element?
A. .html()
B. .setContent()
C. .setHTML()
D. .fill()
Q.34 How do you perform a deep traversal to find all descendants matching a selector in jQuery?
A. .find()
B. .search()
C. .descend()
D. .traverse()
Q.35 How can you clone an element including all data and events associated with it in jQuery?
A. .clone(true)
B. .copy()
C. .duplicate()
D. .replicate()
Q.36 What method is used to get the direct parent of an element in jQuery?
A. .parent()
B. .getParent()
C. .up()
D. .ancestor()
Q.37 How do you remove all child nodes from a specific element using jQuery?
A. .empty()
B. .clear()
C. .removeChildren()
D. .deleteAll()
Q.38 Which method is used to replace all matched elements with new content?
A. .replace()
B. .replaceWith()
C. .replaceAll()
D. .exchange()
Q.39 How do you add a new element to the end of a specific div using jQuery?
A. .appendTo(‘#divId’)
B. .append(‘#divId’)
C. .insertTo(‘#divId’)
D. .attachTo(‘#divId’)
Q.40 What could cause an element to fail to animate as expected in jQuery?
A. Incorrect CSS properties
B. Animation method not supported
C. Syntax errors
D. All of the above
Q.41 Why might an animation not start immediately as expected?
A. Animation queue is full
B. CSS conflicts
C. JavaScript errors
D. All of the above
Q.42 How can you link multiple animations to create a continuous effect without gaps?
A. .link()
B. .chain()
C. .concat()
D. .queue()
Q.43 What is the correct way to slow down an animation effect in jQuery?
A. .slow()
B. .delay()
C. .animate({speed: ‘slow’})
D. .setSpeed(‘slow’)
Q.44 How do you apply a bouncing effect to an animation in jQuery?
A. .bounce()
B. .animate({bounce: ’20px’})
C. .effect(‘bounce’)
D. .jump()
Q.45 Which jQuery method is used to toggle between hiding and showing elements with a sliding effect?
A. .slideToggle()
B. .toggleSlide()
C. .slide()
D. .hideShowSlide()
Q.46 What method is used to execute a series of animations one after another on an element?
A. .queue()
B. .series()
C. .sequence()
D. .chain()
Q.47 How can you animate an element to move to a new position using jQuery?
A. .moveTo()
B. .animate({top: ’50px’, left: ‘100px’})
C. .shift()
D. .relocate()
Q.48 How do you make an element visible with a fading effect?
A. .fadeIn()
B. .visible()
C. .showFade()
D. .appear()
Q.49 What does the .animate() method in jQuery do?
A. Creates CSS animations
B. Manipulates element sizes
C. Performs custom animations
D. None of the above
Q.50 Which method stops all currently running animations on the selected elements?
A. .stopAnimations()
B. .end()
C. .stop()
D. .halt()
Q.51 What jQuery function is used to hide elements with a sliding motion?
A. .slideUp()
B. .slideHide()
C. .hideSlide()
D. .toggleSlide()
Q.52 Which method is used to gradually change the opacity of an element?
A. .fade()
B. .opacityChange()
C. .fadeTo()
D. .transparent()
Q.53 A developer notices that their ‘keydown’ event isn’t working on a dynamically added input field.
What is the likely issue?
A. Incorrect event binding
B. Event delegation not used
C. Outdated jQuery library
D. None of the above
Q.54 If a ‘hover’ event does not fire as expected, what could be a possible cause?
A. Element is hidden
B. Event is not properly bound
C. CSS issue
D. All of the above
Q.55 What might cause a ‘click’ event to trigger multiple times unintentionally?
A. Multiple event bindings
B. Obsolete jQuery version
C. Syntax errors
D. Incorrect selector
Q.56 How do you add a ‘dblclick’ event to an element with the ID ‘dblClickMe’?
A. $(‘#dblClickMe’).dblclick(function())
B. $(‘#dblClickMe’).on(‘dblclick’)
C. $(‘#dblClickMe’).trigger(‘dblclick’)
D. $(‘#dblClickMe’).bind(‘dblclick’, function())
Q.57 Which method is used to attach a single event handler to multiple events in jQuery?
A. .one()
B. .single()
C. .first()
D. .on()
Q.58 What jQuery method would you use to simulate a ‘click’ event on a button?
A. $(‘#button’).simulateClick()
B. $(‘#button’).trigger(‘click’)
C. $(‘#button’).click()
D. $(‘#button’).invokeClick()
Q.59 How do you bind a ‘mouseover’ event to all paragraphs?
A. $(‘p’).on(‘mouseover’, function())
B. $(‘p’).mouseover()
C. $(‘p’).bind(‘mouseover’)
D. $(‘p’).trigger(‘mouseover’)
Q.60 Which jQuery function is used to check whether an event is prevented from its default action?
A. .isDefaultPrevented()
B. .isPrevented()
C. .defaultPrevented()
D. .checkDefault()
Q.61 How do you apply a theme to widgets in jQuery UI?
A. Using CSS files
B. Using the ThemeRoller application
C. Using JavaScript functions
D. Using .theme() method
Q.62 Which jQuery UI widget is used to make a list of items sortable by dragging and dropping?
A. .draggable()
B. .sortable()
C. .selectable()
D. .resizable()
Q.63 What is jQuery UI primarily used for?
A. Adding HTML elements to the page
B. Styling web pages
C. Enhancing user interface interactions
D. Optimizing backend processes
Q.64 How can you troubleshoot a jQuery plugin that behaves differently across browsers?
A. Checking for console errors related to the plugin
B. Testing the plugin across different browser versions
C. Using browser-specific debugging tools
D. Adjusting plugin settings for compatibility
Q.65 What should you check first if a jQuery plugin is not working as expected?
A. The jQuery version compatibility
B. Correct inclusion of the plugin script
C. No conflicts with other scripts
D. Correct plugin initialization method
Q.66 What technique ensures efficient loading of a heavy jQuery plugin on needed pages only?
A. Conditionally loading the plugin based on page content
B. Using asynchronous script loading techniques
C. Applying selective script loading based on user actions
D. Deferring plugin loading until after page load
Q.67 What is a method to enhance or modify a jQuery plugin?
A. By extending the plugin’s functionality through additional scripts
B. By rewriting core functions of the plugin
C. By configuring options provided by the plugin
D. By linking to updated versions of the plugin
Q.68 How do you activate a lightbox plugin on image elements in jQuery?
A. By calling .lightbox() on image selectors
B. By setting a data-lightbox attribute
C. By adding a ‘lightbox’ class to images
D. By including a lightbox attribute in image tags
Q.69 How can you minimize conflicts between multiple jQuery plugins?
A. By using distinct namespaces for plugin functions
B. By loading plugins in a specific order
C. By isolating plugin code in separate files
D. By ensuring plugins do not share global variables
Q.70 What should you verify about a jQuery plugin before integrating it into your project?
A. Its compatibility with your jQuery version
B. Its performance impact on your project
C. Its license and usage terms
D. Its update frequency
Q.71 What should you consider about jQuery plugins to prevent conflicts with existing functions?
A. Their namespacing
B. Their compatibility with other plugins
C. Their method of invocation
D. Their event handling
Q.72 How do you initialize a plugin in jQuery?
A. By calling the plugin’s method on a jQuery object
B. By importing the plugin script
C. By adding a plugin file to the HTML
D. By linking the plugin in the HTML head
Q.73 What is the primary purpose of jQuery plugins?
A. To add new methods to the jQuery library
B. To fix bugs in jQuery
C. To replace jQuery with newer versions
D. To reduce the size of jQuery scripts
Q.74 What could cause an AJAX request to a secure server to fail in terms of security?
A. Cross-origin resource sharing (CORS) restrictions
B. SSL certificate errors
C. Both
D. None of these
Q.75 Why might an AJAX request return a 404 error?
A. The requested resource is not found on the server
B. The server is down
C. The URL is incorrect
D. The data type is mismatched
Q.76 What common issue should be checked if an AJAX call is not initiating?
A. Incorrect URL format
B. Broken server link
C. Misconfigured AJAX settings
D. All of the above
Q.77 What method allows you to modify a part of the webpage asynchronously without reloading the whole page?
A. $.ajax({url: ‘update.php’, success: function(result) {$(‘#div1’).html(result);}})
B. $.updatePart(‘update.php’, ‘#div1’)
C. $.partialLoad(‘update.php’, ‘#div1’)
D. $.loadFragment(‘update.php’, ‘#div1’)
Q.78 How can you attach a success callback that executes after AJAX content is successfully loaded?
A. .done()
B. .success()
C. .complete()
D. .after()
Q.79 Which option in jQuery AJAX is used to handle errors?
A. fail()
B. error()
C. reject()
D. catch()
Q.80 How do you use jQuery to send a form data using AJAX by a POST method?
A. $.ajax({url: ‘submit.php’, type: ‘POST’, data: $(‘#form’).serialize()})
B. $.postForm(‘submit.php’, ‘#form’)
C. $.sendData(‘#form’, ‘submit.php’)
D. $.submit(‘#form’, ‘POST’)
Q.81 What is the use of the timeout option in an AJAX request?
A. To specify the time before a page reloads
B. To set the delay before an AJAX call is made
C. To determine how long an AJAX request should wait for a response
D. To limit the execution time of callbacks
Q.82 How can you handle multiple AJAX requests simultaneously in jQuery?
A. Using the $.when() method
B. Using the $.then() method
C. Using the $.multiAjax() method
D. Using the $.all() method
Q.83 Which jQuery method is best for retrieving JSON data from a server?
A. $.getJSON()
B. $.getScript()
C. $.ajax()
D. $.load()
Q.84 What does the $.post() method do?
A. Sends a POST request to the server
B. Sends a GET request to the server
C. Deletes data from the server
D. Updates data on the server
Q.85 How do you specify the type of data expected back from the server in $.ajax()?
A. Using the dataType option
B. Using the type option
C. Using the method option
D. Using the data option
Q.86 Which method in jQuery is used specifically to load data from the server using a HTTP GET request?
A. $.get()
B. $.post()
C. $.load()
D. $.fetch()
Q.87 What is the purpose of the $.ajax() method in jQuery?
A. To load images asynchronously
B. To send synchronous JavaScript calls
C. To perform asynchronous HTTP (Ajax) requests
D. To reload the page
Q.88 Why might changes to the DOM via jQuery not appear immediately in the browser?
A. Browser caching
B. DOM is not updated
C. JavaScript is paused
D. Synchronous processing issues
Q.89 What could be the reason if .remove() is not removing an element as expected?
A. Element is not selected correctly
B. Syntax error in jQuery
C. Element is hidden
D. Element is locked
Q.90 How do you dynamically change the style of an element based on certain conditions in jQuery?
A. .css(‘style’, ‘value’)
B. .style(‘style’, ‘value’)
C. .changeStyle(‘style’, ‘value’)
D. .alter(‘style’, ‘value’)
Q.91 What is a recommended practice when loading multiple JavaScript libraries including jQuery?
A. Load libraries synchronously
B. Load libraries in the footer
C. Use a single minified file for all libraries
D. Use asynchronous loading methods
Q.92 What strategy should be adopted to handle potential conflicts when integrating jQuery with another library?
A. Loading jQuery first
B. Defining all libraries in separate JavaScript files
C. Using aliasing for jQuery
D. Loading all libraries asynchronously
Q.93 How does jQuery ensure compatibility when used alongside other JavaScript libraries?
A. By automatically adjusting its methods
B. By using its own version of the JavaScript engine
C. By using a compatibility mode
D. By minimizing its footprint
Q.94 What is the primary function of the jQuery.noConflict() method when using jQuery with other libraries?
A. To import other libraries into jQuery
B. To enhance jQuery performance
C. To relinquish control of the $ symbol
D. To merge two libraries
Q.95 How do you identify and resolve performance bottlenecks caused by jQuery selectors?
A. Use browser performance tools to analyze selector efficiency
B. Simplify selectors
C. Increase specificity of selectors
D. All of the above
Q.96 What should be checked first if jQuery animations are slow and jittery?
A. Check if CSS transitions could be used instead
B. Ensure no heavy scripts are running concurrently
C. Verify jQuery version compatibility
D. Optimize image sizes
Q.97 How can jQuery’s .detach() method be utilized to enhance performance when modifying DOM elements?
A. Detaching elements, making modifications, and reattaching
B. Simply removing elements temporarily
C. Clearing content before reinsertion
D. Using it instead of .remove()
Q.98 What technique should be used to append multiple elements efficiently in jQuery?
A. Appending each element individually
B. Creating a string of HTML and appending once
C. Using a document fragment
D. Looping through an array of elements
Q.99 How does minimizing the number of global selectors improve jQuery performance?
A. Reduces the scope of each search
B. Lowers memory footprint
C. Decreases the chance of selecting unintended elements
D. All of the above
Q.100 What is the impact of chaining multiple methods in jQuery?
A. Reduces readability
B. Increases execution time
C. Optimizes performance by reducing the scope of DOM traversal
D. Can lead to errors
Q.101 Why is it advisable to use event delegation in jQuery?
A. Reduces memory usage by handling events at a parent level
B. Increases the number of event handlers
C. Simplifies code complexity
D. Enhances page loading speed
Q.102 What jQuery function is most effective for minimizing DOM access?
A. .closest()
B. .find()
C. .children()
D. .end()
Q.103 What is an effective approach to troubleshoot performance issues with jQuery animations on a complex page?
A. Checking for excessive DOM manipulations
B. Optimizing event handlers
C. Utilizing jQuery’s Performance tool
D. Implementing throttling or debouncing techniques
Q.104 What should you investigate if a custom jQuery plugin does not trigger events as expected?
A. Plugin’s event binding
B. Conflict with jQuery versions
C. Syntax errors in event names
D. Incorrect method calls
Q.105 How can you implement a jQuery method that supports promise-like behavior for asynchronous operations?
A. Using .defer()
B. Using .promise()
C. Using .async()
D. Using .wait()
Q.106 What method can be used to extend jQuery’s default settings for all AJAX requests?
A. .extendAjax()
B. .ajaxExtend()
C. .ajaxSetup()
D. .setupAjax()
Q.107 How do you attach a global AJAX event handler that fires whenever an AJAX request completes?
A. $(document).ajaxComplete(function() {})
B. $.on(‘ajaxComplete’, function() {})
C. $.ajaxSetup({complete: function() {}})
D. $(document).on(‘ajaxComplete’, function() {})
Q.108 How does jQuery handle custom events and what are they used for?
A. Custom events are used to handle native browser operations
B. They’re used to manage AJAX requests exclusively
C. They allow developers to define and trigger their own events
D. They are a method to speed up event handling
Q.109 What is the purpose of the jQuery.noConflict() method?
A. To avoid conflicts with other JavaScript libraries that use the $ symbol
B. To reset jQuery variables
C. To clear all jQuery data from a page
D. To reload jQuery settings
Q.110 How can you use jQuery to dynamically load a script?
A. Using the .loadScript() method
B. Using the .getScript() method
C. Using the .ajax() method with a script parameter
D. Using the .script() method
Q.111 What is “chaining” in jQuery?
A. Linking several methods on different jQuery selectors
B. Connecting similar events into a single handler
C. Applying multiple methods in a single, continuous line of code on the same element set
D. Combining multiple CSS files into one request
Q.112 How does the .delegate() method function in jQuery?
A. It triggers a delegated event
B. It attaches a handler to the parent for any event that occurs on matching children
C. It directly binds events to elements
D. It replaces all previous events
Q.113 How can you solve an issue where a jQuery UI dialog does not open?
A. Check if the dialog div is hidden
B. Ensure the .dialog() is correctly called
C. Verify there are no JavaScript errors in the console
D. All of the above
Q.114 What should you check if a jQuery UI widget is not responding to user interactions?
A. jQuery UI is not loaded
B. The widget’s script is corrupted
C. The browser is incompatible
D. JavaScript is disabled in the browser
Q.115 How do you create a custom animation effect on a dialog box using jQuery UI?
A. .dialog({effect: “bounce”})
B. .dialog({show: {effect: “bounce”, duration: 1000}})
C. .animateDialog(“bounce”)
D. .dialogAnimate(“bounce”)
Q.116 What jQuery UI method is used to make an element resizable?
A. .resizable()
B. .makeResizable()
C. .enableResize()
D. .setResizable()
Q.117 How do you initialize a datepicker on a text input field in jQuery UI?
A. $(“#date”).datepicker()
B. $(“#date”).initDatepicker()
C. $(“#date”).setDatepicker()
D. $(“#date”).createDatepicker()
Q.118 How can you prevent a dialog from closing on jQuery UI?
A. Using the .preventClose() method
B. Modifying the closeText option
C. Setting the modal option to true
D. Overriding the close event
Q.119 Which method is used to disable a jQuery UI button?
A. .disableButton()
B. .button(“disable”)
C. .disable()
D. .buttonDisable()
Q.120 What is the purpose of the .dialog() widget in jQuery UI?
A. To display messages
B. To create a popup window
C. To confirm user actions
D. To display forms
Q.121 How do you ensure that jQuery code is future-proof, especially concerning deprecations and changes in the library?
A. Regularly updating the code according to the jQuery migration guide
B. Ignoring deprecation warnings
C. Using older versions of jQuery indefinitely
D. Using only core jQuery features
Q.122 What should be verified to ensure a jQuery script that works in development also functions correctly in production?
A. Checking for any CORS issues
B. Ensuring all external resources are correctly loaded
C. Verifying that the jQuery version matches
D. Confirming script load order
Q.123 What strategy is effective for debugging jQuery code that interacts with a lot of dynamic content?
A. Setting breakpoints in all scripts
B. Logging all actions in the console
C. Using the MutationObserver API
D. Inspecting elements in real time
Q.124 How should you handle jQuery AJAX requests to ensure they are maintainable and scalable?
A. By using the global .ajaxSetup() for all configurations
B. By customizing each request with specific parameters
C. By always using synchronous requests
D. By limiting AJAX calls to client-side operations only
Q.125 What is the best practice for attaching event handlers to elements that are dynamically added to the DOM?
A. Using .click() directly on the elements
B. Using .on() delegated from a static parent
C. Using .bind() on each element individually
D. Using .live() on document
Q.126 How can minimizing the use of global selectors improve jQuery performance?
A. It reduces the chance of selecting unintended elements
B. It limits the scope of each search, reducing processing time
C. It enhances security
D. It simplifies debugging
Q.127 What is the advantage of using method chaining in jQuery?
A. It reduces the readability of code
B. It increases execution speed by minimizing DOM access
C. It simplifies the syntax
D. It increases memory usage
Q.128 Why is it recommended to load jQuery from a CDN?
A. Faster load times due to cached versions
B. It is more secure
C. It provides automatic updates
D. It requires less configuration
Q.129 How do you address intermittent test failures in jQuery, especially those caused by asynchronous operations?
A. Increasing timeout settings
B. Refactoring the tests to handle asynchronous results
C. Running the tests multiple times
D. Ignoring the failures
Q.130 What should you do when a jQuery test unexpectedly fails after recent changes to the code?
A. Revert all changes
B. Run the test in a different environment
C. Check the change log for clues
D. All of the above
Q.131 How can breakpoints be useful in testing jQuery code?
A. They can pause execution at critical points
B. They can modify code on the fly
C. They can bypass errors
D. They can simulate server responses
Q.132 What is a quick method to verify that jQuery is triggering the correct events during testing?
A. Checking the event log in the browser’s developer console
B. Using alert boxes
C. Using console.log in event handlers
D. Rewriting the event handlers
Q.133 How can you simulate user interactions in jQuery code testing?
A. Using $.trigger() to mimic events
B. Using .click() to force actions
C. Using setTimeout()
D. Using manual testing
Q.134 Which tool is commonly used for writing automated tests for jQuery functions?
A. Selenium
B. Jasmine
C. QUnit
D. Mocha
Q.135 What role does automated testing play in maintaining jQuery code?
A. It helps prevent regressions by automatically testing code changes
B. It replaces manual testing completely
C. It only tests new code
D. It simplifies the debugging process
Q.136 How does integration testing differ from unit testing for jQuery code?
A. Integration testing combines all modules and tests them as a group
B. Integration testing tests a single function at a time
C. Integration testing is only for client-side scripts
D. Integration testing is quicker
Q.137 What is the primary purpose of unit testing in jQuery code?
A. To check for syntax errors
B. To ensure that each function works as intended
C. To enhance performance
D. To simplify code
Q.138 How can you identify memory leaks in jQuery applications?
A. Monitoring memory usage over time in browser tools
B. Checking for detached DOM elements
C. Both
D. None of the above
Q.139 What debugging technique can provide insights into the sequence of jQuery event firing?
A. Adding console.log() statements within event handlers
B. Using performance profiling tools
C. Monitoring network requests
D. Setting conditional breakpoints
Q.140 What is a significant benefit of using .on() for event delegation in jQuery for dynamic content?
A. It reduces memory usage by managing fewer event handlers
B. It allows easier management of events
C. It isolates event handlers
D. It simplifies event handler updates
Q.141 What is a simple check to ensure that a jQuery selector is working as expected?
A. Verify the selector in the console
B. Change the selector until it works
C. Use a default selector
D. Ask a colleague for help
Q.142 How can you use the .error() method in jQuery for debugging?
A. Attach it to load events to handle errors
B. Apply it to any jQuery object
C. Use it to log errors in AJAX requests
D. It’s deprecated
Q.143 Which jQuery function is essential for checking whether the DOM is fully loaded before running script?
A. $(document).ready()
B. $(window).load()
C. $(document).start()
D. $(document).init()
Q.144 What is an effective strategy for debugging complex jQuery selectors?
A. Break down selectors into simpler parts
B. Use only ID selectors
C. Avoid using CSS classes
D. Use inline styles instead of selectors
Q.145 How can “linting” tools be beneficial for jQuery code debugging?
A. They automatically correct syntax errors
B. They optimize code performance
C. They help identify syntax and other errors
D. They encrypt the code
Q.146 What is the first step in debugging jQuery code?
A. Checking the jQuery version compatibility
B. Reviewing the console for errors
C. Ensuring jQuery is properly loaded
D. Verifying HTML structure
Q.147 How can you identify and resolve script execution order issues when using jQuery with other libraries?
A. Use script loaders
B. Adjust the order of script tags manually
C. Both
D. Implement callbacks for dependent scripts
Q.148 What diagnostic approach should be used if jQuery scripts conflict with another library after an update?
A. Review the jQuery migration guide
B. Check for deprecated methods
C. Examine the console for errors
D. All of the above
Q.149 How do you extend jQuery’s capabilities in a way that minimizes conflict with other loaded libraries?
A. By modifying jQuery’s prototype directly
B. By adding new methods using jQuery.fn.extend()
C. By rewriting existing jQuery methods
D. By isolating jQuery in an IIFE
Q.150 How can you safely use jQuery in noConflict mode while using another library that also uses $?
A. var jq = jQuery.noConflict();
B. jQuery.noConflict(true);
C. var $j = $.noConflict();
D. var $j = jQuery.noConflict();
