What Is jQuery?
jQuery supports all popular browsers, and is utilized by companies with some of the largest presence on the web:
Before you can benefit from your jQuery skill set, you need to get past the hurdle of interviewing successfully for the position. So it?s critical to anticipate the questions a potential employer will ask, and the answers they will be looking for.
jQuery Interview Questions
As a knowledgeable jQuery developer, you should be ready for and able to answer these questions in an interview:
Name some of the most useful features of jQuery
jQuery can be used by developers to:
How is the document.ready() function different from body.onload()?
There are 2 significant differences:
What are some advantages of using jQuery?
What are jQuery selectors? How do you use them?
What are jQuery selectors? How do you use them?
In jQuery, these selectors are the same as those you're used to with CSS.
What is the difference between width() and css(?width?)?
You have two ways to change the width of an element in jQuery. The difference between the two is in the value or data type returned from each function:
When using css(?width?) you must provide the ?px? operand for the width value, where with width() you do not have to pass that value
Using css(?width?) will provide the value ?300px?, but width() returns only the integer value 300
Describe how to create and work with cookies with jQuery
Cookies can be read, created, and deleted with the Dough plug-in
How can you hide an image when a button is clicked in jQuery?
jQuery provides very effective functionality for event handling. When you find an image, using either an ID or class, that you want to hide based on detecting the ?ButtonToClick? event, specifying the hide() option will hide the image specified.
Are there advantages to using the minimized version of jQuery?
Yes ? minimized version of the jQuery js file can be as much as 50% smaller than non-minimized js files, resulting in faster loading of web pages.
Explain the difference between children and find methods in jQuery.
Find method will discover all levels down the DOM tree. Children will find only a single level down the tree.
What is a jQuery connect, and when would you use it?
jQuery connect is actually a plug-in used to connect a function with some other function. You would use jQuery connect when you want to execute a function from some other function or plug-in. You can download jQuery connect from the jQuery website, then use the $.connect function to include the plug-in in your HTML.
What is the purpose of the jQuery load method?
jQuery load function is a method whereby you can load data from a server and assign the resulting data into the desired element without loading the web page. This can improve performance of the application.
Describe the purpose/use of the jQuery filter
jQuery filter can filter the values from an object list based on filter criteria. This could be used, for example, to select employees from certain states from a personnel database.
Is jQuery scripting utilized on the client or server side?
jQuery is scripting on the client side. jQuery code is executed within client browser functions.
Are there performance variations between jQuery selectors?
Yes ? ID and element selectors are the fastest, while class selectors are the slowest.
What is the application of the ?each? function in jQuery?
Each function allows you to loop through all elements of a target object. This can be effective when utilizing multi-element DOM, object properties and looping arrays.
Are you locked into using jQuery?s $ character in your code?
No ? utilizing the ?NoConflict? method, you can replace the $ with a stored variable of your choice.
Is there an easy or designated way to debug jQuery functions?
Yes ? jQuery can be debugged in two different ways with the debugger keyword:
Explain the use of .empty(), .detach(), and .remove()
Remove method is used when you need to remove all the matched elements. This removes all the jQuery data that is associated those matched elements.
Detach functions the same as remove, with the exception that it does not remove the jQuery data associated with the elements.
Empty method removes all the child elements from the matched elements
How would you add an HTML element in a DOM tree?
jQuery element method appendTo() adds an element to a DOM tree. jQuery provides many methods for manipulating DOM content. You can add either a new HTML element or an existing element.
What is jQuery method chaining, and why would you use it?
Calling a method as a result of another method is called method chaining. Method chaining provides easily-read and clean code, and also can provide better performance by providing a single search over a DOM.
What is the difference between the .get() method and the jQuery .ajax() method?
Get() is a specific function over ajax to retrieve data. Ajax() is more configurable and powerful, allowing you to not only specify how long to wait for a response, but also how to handle error conditions.
Can you add or remove CSS classes with jQuery?
Yes ? this is a very handy function of jQuery. By applying the addClass() and removeClass() methods, jQuery developers can dynamically alter the class of elements, such as making them active or inactive.
How would you set an attribute in jQuery?
The jQuery attribute method ? attr() ? will alter the named attribute with the new value specified on the method.
What is the difference between the prop() and attr() methods?
Each method is used to set or get the property of an element?s attribute. The difference is that prop() returns the current value of the property, where attr() returns the default value.
You can retrieve the attribute of any HTML element. Select the links (all links or only specified links) using a jQuery selector then set the attribute as applicable.
What is the jQuery .data() method used for?
Getting Started in jQuery Development
As a knowledgeable jQuery developer, you should be ready for and able to answer these jQuery interview questions easily.
If you?re just getting started in jQuery coding, there are courses available online that will not only teach you the basics, but even provide certification, which can give you an advantage to prospective employers.