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UI Developer Interview Questions
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What are the jQuery effects methods?
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Last Updated: Jun 14, 2024

UI Developer Interview Questions

Author Prerna Tiwari
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In this blog, we will be discussing UI Developer Interview Questions.UI developers use front-end technology to bring creative software concepts to life. They are in charge of creating user interfaces that communicate the program's backend capabilities. It is their responsibility to ensure that the user interface meets their expectations. A well-designed user interface will ensure that the user and the product interact effectively. This is accomplished through the use of a clean and responsive design. If you aspire to become a UI developer, you have come to the right place.

This blog features the top 30 UI developer Interview Questions. Now, without wasting time, let's get started with some important UI developer interview questions.

UI Developer Interview Questions

1. What is HTML?

HTML is an abbreviation for HyperText Markup Language. It is the most widely used markup language for creating websites and other web-based content. You can earn extra points by learning HTML HISTORY and throwing in obscure facts.


2. Can you explain the distinction between HTML elements and tags?

HTML elements instruct the browser on how to render text. They become HTML tags when surrounded by angular brackets >. Tags are typically used in pairs to surround the text.


3. How do you optimize the assets of a website?

Following are some of the methods of optimizing the assets of a website:

  • File concatenation
  • File compression
  • CDN hosting
  • Asset offloading
  • Code reorganization and refinement


4. What does DOCTYPE stand for?

The term DOCTYPE informs the browser about the type of HTML used on a webpage. Browsers, in turn, use DOCTYPE to determine how to render a page. Failure to use DOCTYPE or the incorrect DOCTYPE may cause your page to load in Quirks Mode.


5. What should you avoid when designing or developing multilingual websites?

  • Using Unicode encoding
  • Being aware of text direction and standard font sizes
  • Using the 'lang' attribute
  • And language word length (may affect layout).


6. What is "Semantic HTML"?

Semantic HTML is a coding style in which the tags represent the meaning of the text. Tags such as bold and italic should not be used in Semantic HTML because they only represent formatting without providing any indication of meaning or structure. The semantically correct way to use these tags will produce the same italic and bold effects while demonstrating structure and meaning (emphasis in this case).


7. What are the methods for decreasing page load time?

Reduce image sizes, remove unnecessary widgets, use HTTP compression, place CSS and script references at the bottom or in external files, minimize lookups, redirects, caching, and so on.


8. What are standards and quirks mode?

Browser layout engines operate in three modes:

  • Quirks mode:- Layout emulates nonstandard behaviour in Navigator 4 and Internet Explorer 5. These were required for websites created prior to the introduction of web standards.
  • Full standard mode: The behaviour described in this mode is the same as that described in HTML and CSS specifications. The majority of modern browsers use full standard mode.
  • Almost standard Mode: There are very few quirks implemented in almost standard mode.


9. What are the constraints of serving XHTML pages?

Perhaps the most serious issue is the current lack of browser support for XHTML. XHTML cannot be parsed as XML by Internet Explorer and many other user agents. As a result, it is not the extensible language that was promised.


10. How do you leave comments without the browser picking up on the text?

Comments are used to explain code and prevent code from being recognized by browsers. 

Comments begin with a "*" and end with a "–>."


11. What is the distinction between a link to an image, a link to a website, and a link to an email address?

Link to an image

Link to a website

Link to an email address

The image (img) tag is used to include an image on a webpage.

The anchor (a) tag is used to include an image on a webpage.

The anchor(a) tag is used to specify a webpage's email address.


The image's path or address is placed in the image tag's source(src) attribute.


The path or address of the website is placed in the anchor tag's hyperlink reference (href) attribute.

The email address is placed in (href) attribute, with a mail to property at the beginning.


12. My hyperlink or image is not displaying properly; what is the problem?

It could be a variety of things, but the most common errors are missing a tag bracket or a quote for href, src, or alt text. You should also cross-check the link.


13. What is the syntax distinction between a bulleted and numbered list?

Bulleted lists use the ul > tag, which stands for "unordered," whereas ordered lists use the ol > tag.


14. What are the differences between absolute, relative, static, and fixed positions?

Static: It is a default position; the system will set the unchangeable default values if no position or value is specified for elements. The system employs a first-come, first-served strategy. That is, whatever comes first will be shown first.



position: static is the syntax.


Relative: You can use relative to change the position of the elements. When you change the position of an element to a relative, it changes the position of the elements by using the attributes listed below. The following are the attributes:

  1. Alignment: In this attribute, you can specify values such as the top, bottom, right, or left depending on how the position of the element changes.
  2. Size: Indicate in pixels.


Absolute: The user can change the element's position, and the absolute will generally place relative to the parent. If a parent is unavailable on the page, it is placed in a relative position by default.





Fixed: The relative element will be placed in the browser window or viewport. The viewport does not change when scrolling. As a result, the element's position is fixed.





15. What exactly is a responsive website?

A responsive website fits any system screen resolution device type, looks good at any size, and is understandable to the user.

See this, Power Apps Interview Questions


16. What is the distinction between inline, inline-block, and block?




It always starts on a new line and takes up the entire right and left horizontal space on the web page.

These elements do not begin on a new line. They are both in the same line.

Inline blocks combine the ability to contain the element's contents to a rectangle with the ability to position the element against the layout of the page flow, as an inline element would.

It can modify the page's margins and padding.


You cannot add space to the page's top and bottom paddings, but you can add space to the left and right of an inline element.


It can modify the page's margins and padding.


Tags are examples of the block.


Inline elements include span, strong, and img tags

For example, when we want to change the style of A to look like a regular button, we use Inline-block.


17. Is a compiler required for HTML?

No, because HTML is a front-end language, it does not require a compiler, whereas Java, C, and C+ require a compiler to convert the code into machine-readable language.

18. What is the distinction between a document and a window?


The window is the first thing that appears when you open the browser. It has characteristics such as inner width, inner height, length, and name.

Inside the window object, the Document is loaded. It is similar to HTML, PHP, and other documents loaded into a browser and has properties such as title, URL, cookies, and so on.


19. What exactly is web accessibility?

Web accessibility entails making a website accessible to people who are differently abled or disabled. So that people with disabilities can understand, navigate, and interact with the web easily.


20. What's the distinction between HTML and XHTML?

Full form HyperText Markup LanguageExtensible HyperText Markup Language
IntroductionHTML is used for creating web pages and other information that can be displayed in a web browserXHTML is a family of XML markup languages that extend versions of the widely used HTML.
Extension.html, .htm.xhtml, .xht, .xml, .html, .htm
NatureFlexible framework requiring lenient HTML-specific parser.The restrictive subset of XML needs to be parsed with standard XML parsers.
ApplicationApplication of Standard Generalised Markup Language (SGML).Application of XML


21. Can you explain the distinction between local storage, session storage, and cookies?

Local storage: It enables data storage without regard to expiry dates.

Cookies: They allow data to be stored within the client-server system.

Session Storage: It saves the data entered when the window is opened.


22. How can you improve page performance?

The following are a few steps to improve page performance.

  • Image size should be reduced.
  • Delete the cache.
  • Reduce the number of external HTTP requests.
  • Asynchronously load the JavaScript.
  • Make your website mobile-friendly.


23. What is JavaScript hoisting?

This was a common UI Developer Interview question. The first step in accessing variables in javascript is declaring the variables. If variables are defined at the bottom of the script, but JavaScript throws them before they are defined, the variable is undefined. Only assigned variables are hoisted in JavaScript.


24. Can you describe the new HTML elements?

Semantic tags, multimedia and graphics tags, and other new elements are used to change some of the features in HTML. A figure, header, footer, mark, and multimedia are examples of semantic tags, while audio and canvas are examples of graphics tags.


25. What is JavaScript event bubbling?

Event bubbling is a method of event propagation in the HTML DOM API that occurs when an event occurs in one element inside another and both elements have registered a handle for that event. The event is captured and handled by the innermost element first, and then propagated to the outer elements via bubbling. The execution begins with that event and proceeds to it.


26. What are local and session storage?

Local Storage – Data is not sent back to the server for each HTTP request (HTML, images, JavaScript, CSS, and so on), reducing client-server traffic. It will remain until manually cleared via settings or program.

Session Storage – Session storage is similar to local storage; however, unlike data stored in local storage, data stored in session storage is cleared when the page session ends. When the browser is closed, Session Storage is removed.


27. What is the difference between null and undefined in javascript?

Undefined indicates that a variable has been declared but not yet assigned a value. Null, on the other hand, is an assignment value. It can be assigned to a variable as a no-value representation. Furthermore, undefined and null are distinct types: undefined is a type in and of itself (undefined), whereas null is an object.


28. What is an AJAX request, and how should we use one?

AJAX is an acronym for asynchronous JavaScript and XML, and it is a JavaScript client-side process. It is used to retrieve or post data from a remote server without requiring the page to be reloaded.


29. How do you use HTML5 new tags in Internet Explorer 8 and earlier?

HTML5 semantic tags such as article, figcaption, footer, header, navigation, and section are not supported by HTML4-based browsers, including Internet Explorer 8. However, you can run these elements in older browsers by using html5shiv.js.


30. In JavaScript, what are the scopes of variables?

A variable's scope is the area of your program where it is defined. There will only be two scopes for JavaScript variables.

• Global Variables A global variable has global scope, which means it can be seen throughout your JavaScript code.

• Local Variables A local variable is only visible within the function in which it is defined. Function parameters are always function-specific.

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Frequently Asked Questions

What are the jQuery effects methods?

The following are some jQuery effects methods:

  • Show () displays the elements that have been chosen.
  • Hide (): Hides the elements that have been selected.
  • Toggle (): It toggles between the hide() and show() methods, displaying or hiding the selected elements.

What can you do to improve the performance of your website?

You can improve the page's performance by doing the following:

  • Image size-reduction
  • Delete the cache
  • lowering the number of external HTTP requests
  • Making your website mobile-friendly
  • removing extraneous widgets

How do you optimize the assets of a website?

You can optimize a website's assets by doing the following:

  • Concatenation of files
  • Compression of files
  • CDN Web Hosting
  • Asset disposal
  • Code reorganization and refinement


We have extensively discussed the UI developer interview questions in this article in detail. This blog features 30 UI developer Interview Questions.

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