If you're looking for jQuery Interview Questions & Answers for Experienced or Freshers, you are at right place. There are lot of opportunities from many reputed companies in the world. According to research jQuery has a market share of about 45%. So, You still have opportunity to move ahead in your career in jQuery Development. Mindmajix offers Advanced jQuery Interview Questions 2019 that helps you in cracking your interview & acquire dream career as jQuery Developer.
jQuery can simply be interpreted as most advanced JavaScript framework which is used for performing high-level applications which include feature-rich, fast,and lightweight framework which assists in to through the HTML DOM, add Ajax interaction,build animations, manipulation of the page content, modify the alignment and render cool UI effect. This is a client-side scripting language.
The difference between the jQuery and the JavaScript can simply be explained.
JavaScript can simply be interpreted as a high-level application language whereas, jQuery can be interpreted as a library which is built within the JavaScript language & helps in the better functioning of JavaScript.
jQuery can be interpreted as an internally built library which is being used in the JavaScript.
And jQuery is strictly been designed with the functionality of client-side scripting. jQuery is not compatible with server-side scripting.
In order to get begin with the jQuery, all that one needs to do at the beginning is to make a reference to its complete library. After this, you will be having access to all the application files which are present within the library. jQuery latest version can now get downloaded from jQuery.com.
jQuery is a highly programmed internal library for the better functioning of JavaScript. It handles a number of applications and its prominence can never be ignored. The following list will be depicting the reasons for why is the need to use jQuery?
* jQuery comes very handily for the purpose of designing user-friendly web applications.
* By making an effective use of jQuery the performance of an application can be greatly enhanced.
* Very fast and extensible.
* Only minimal lines of codes will be sufficient for writing UI related functions.
jQuery has a set of methods implying which we can expect to provide different effects within the system. Some of the jQuery methods include
* FadeOut()
* Toggle()
* Hide()
* Show()
* FadeIn() and
With the minimized version of the jQuery, the efficiency of the webpage can be greatly improved. The effectiveness of the webpage which is having a minimized version of jQuery will be a lot better than the effectiveness of the webpage which is having a normal js file.
This is the reason why most of the web pages are nowadays are found to have a minimized version of the jQuery.
jQuery is a highly advanced library application which extensively is used in following scenarios:
* Apply CSS static or dynamic functions.
* Calling functions on events.
* For the purpose of manipulation.
* For creating different animation effects.
Having the presence of all the advanced library applications jQuery is best at maintaining different applications with a higher degree of effectiveness.
jQuery connect can simply be interpreted as a plug-in which is used to connect or bind one function to the another. This will be helpful for executing the fro any other function or the plug-in is executed.
JQuery Ajax method makes use of four different parameters which include
* URL – The URL must be clearly specified in order to send the request.
* type – Specifies the type of request(Get or Post)
* data – Specifies data to be sent to the server
* Cache – This tells if the browser should index the specific page or not.
Including jQuery in a page can be done with the help of the following ways.
* Local copy inside script tag
* Remote copy of jQuery.com
* By keeping a remote copy of Ajax API
* Making a local copy of script manager control
* Embedded script using client script object
Just like they are used in the CSS, both ID selector and Class selector are used for the same functioning .
In order explain the functioning of both the concepts in simpler words, ID selector uses ID while class selector makes use of a class to select the different elements.
In the case where you are needed to select only one element then we have to go with the ID selector. And if you want to select a group of elements, then we have to go with the class selector.
The animate function is extensively being used in the jQuery. It is an advanced concept which is well received by the audience. Well, the main feature of the animation function in jQuery is to apply the custom animation effect to different elements.
The syntax for this function is as follows
Syntax:
$(selector).animate({params}, [duration], [easing], [callback])
Here,
* "param" defines the CSS properties where are intended to apply the animation.
* "duration" it simply depicts for what exact period of time the animation will run. Its values are: "slow", "fast", "normal" or it can even be milliseconds.
* "easing" is the string which specifies the function for the transition.
* "callback" it is the function with the help of which we can call an action upon the completion of the animation.
In order to help the system to overcome the conflicts between the different libraries and frameworks the jQuery no-conflict option given by the jQuery. This concept is really advanced which has been developed over the recent times. In the case of any conflicts which arise between the libraries and frameworks using this jQuery.noConflict function will help in overcoming all the conflicts.
1. In jQuery there are three different applications applying which we can avail the fade effect.
Fade effect can be availed by using the functions which are fadeIn, fadeOut and fadeTo.
2. The opacity of elements gets changed with animation through the effect of these methods.
The syntax for the fading effect includes
Syntax:
$(selector).fadeIn(speed,callback)
$(selector).fadeOut(speed,callback)
$(selector).fadeTo(speed,opacity,callback)
“speed” this can be one among the following values: “slow”, “fast”, “normal” or milliseconds.
“opacity” this is used to specify the capacity of fading to give opacity.
“callback” it is the function with the help of which we can call an action upon the completion of fading.
The struts2 jQuery plug-in is used to:
* Easy integration of Ajax and widgets will be provided to the user.
* The extent of coding needed to be done will be reduced.
For ex:
Result Div
The advantages of using truts2 jQuery are:
1. It greatly reduces the extent of coding needed to be done for a particular action.
2. It also supports ajax form validation.
3. The readability levels of the code will be very high and so it will become much easier to perform the debugging.
Information of an element can be stored in the simple javascript by simply adding a domain object model property to the element. This results in the rising of issues such as leakage of memory in the browsers.
But in the case of jQuery the user does not need to be bothered by the memory management issues.
For ex : Storing and retrieving data related to an element:
$(‘#myDiv’).data(‘keyName’, { foo : ‘bar’ }); $(‘#myDiv’).data(‘keyName’); // { foo : ‘bar’ }
The procedure of extracting a query string with regular expressions can be done in two ways.
1. Approach of String-based:
It is considered to be the simplest way in use for extracting a query string with regular expressions. This method is carried ahead by making the utilisation of the .replace() method to function.
For ex :
var data = string.replace("http://localhost/view.php?", "");
The above procedure will be fine but it has some flexible issues.
2. Regular expression approach:
This is the most powerful method for extracting a query string and the pattern must be used that seeks about the question mark among the string. When done, the JS regular expressions are delimited
jQuery library has two different versions Development and Production. The other name for the deployment version is minified version.
Considering the functionality, both the files they are much similar to each other. Being smaller in size, the .min.js gets loaded quickly saving the bandwidth.
The term CDN relates to the concept of Content Delivery Network. In general, CDN can be interpreted as a large system of servers that are deployed in multiple data centers across the internet.
CDN is mainly aimed at delivering the content to the end-users by enabling them to have high availability and high performance.
The benefits of CDN are quite effective in relation to the working functionality of the jQuery.
Some of the benefits of the CDN include
* CDN greatly diminishes the load from your server.
* Saving the bandwidth CDN helps the jQuery to load faster than the usual time
* The most prominent feature of the CDN is that it if any user visits a website which is running on jQuery it caches it.
The event.preventDefault() method function is to stop the default action of an element from taking place or to halt the default action from happening.
The main differentiating factor of onload() and document.ready() is that
At max, a page supports the existence of only one onload function, & all the other onload functions will be getting terminated
While coming to the document.ready function, a page can have more than one document.ready function.
Also, the document.ready function is called when the DOM gets loaded and whereas the onload function gets called only when the DOM images get loaded on the page.
In general, jQuery is considered to be far better than the JavaScript. jQuery can be interpreted as an application for developing Ajax application and helps in simplifying the code & the code readability will also be good.
jQuery also supports the creation of animations and delivers such high-level functionalities.
Related Page: AngularJS Vs. JQuery
There are three types of selectors in jQuery:
* CSS Selector
* XPath Selector
* Custom Selector
The concept of grouping can simply be explained as whenever the same declaration gets shared by more than one selector they get separated by a common separated list.
This helps in greatly reducing the size of the CSS and helps it in making it become more readable.
In order to stop all the queued animations and to help them place in their final state the .finish() method is used. This method was introduced in jQuery 1.9.
The .finish() method will be quite similar to .stop(true, true). It helps in clearing the queue & thereby helps the animations to enter into their end state. In .finish() it also causes the CSS property of all queued animations to jump to their end values, as well.
The latest version (when this post is written) of jQuery is 1.10.2 or 2.0.3. jQuery 2.x has the same API as jQuery 1.x but does not support Internet Explorer 6, 7, or 8.
We can write browser specific code by simply making use of the jQuery.browser property. This property contains flags for the user agent, read from navigator.userAgent.
This property was excluded from jQuery 1.9.
By using $.type(Object) which returns the built-in JavaScript type for the object.
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