While it may be a stretch to call any IT career recession-proof, there is little doubt that the digital age has created and sustained enormous demands for professionals in a wide range of disciplines and skillsets.

It’s a job-seekers’ market for many IT occupations, but even so, it’s essential to make sure that you make the best first impression during an interview. After all, you not only need to impress the interviewer with your knowledge, you also need to show why you’re apart from the pack in a class by yourself.

Brushing up on the questions you’ll most likely get during a job interview is excellent preparation. Bear in mind; this isn’t a replacement for knowing the material; it’s a refresher, something meant to fill in small gaps in your memory. Even if you’re already in a user interface (UI) position, there may be some upskilling in your future. These questions, taken in conjunction with some refresher courses, are a valuable tool that can help facilitate the whole upskilling experience.

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Below are two dozen interview questions and answers that may be asked of UI developer job candidates. UI developers are the third most in-demand professionals today in the IT industry. Well-designed UI is essential to the success of new software applications.

We’ll start with basic questions and work up to the more complex ideas. Let’s go.

Basic Questions

Q: What exactly is the role of a UI developer?

A: The best way to answer this is to define what a user interface is. UI is every detail that users can control or interact with (keyboard, mouse, touchscreen, other controllers, etc.) across different devices such as smartphones, desktop computers, laptops, tablets, and other mobile technology. The UI developer’s role is to create the best, most convenient interface that meets the users’ needs, such as ease of use, accessibility, and aesthetics.

Q: What’s the difference between a UI developer and a UX developer?

A: Although these disciplines often overlap, a UI developer is responsible for designing the visual, interactive elements, something that helps users navigate their way through the product. A user experience (UX) developer creates and improves the quality of a user’s interaction with both the company and its product. If UI and UX were part of the human body, UI would be the skin and appearance, while UX would be the internal organs.

In summary, a product that looks nice but doesn’t work well has useful UI and bad UX. If the product works great but is an eyesore, it has superior UX but inferior UI.

Q: What’s the difference between a UI developer and a front-end developer?

A: Front-end developers create the client-side of a web interface, making sure it functions properly, such as making sure all of the website’s elements work. The UI developer makes everything on the site is user-friendly and looks good.

Q: What kind of skills do you think are crucial for a successful UI developer?

A: UI developers must have skills in visual design (including animation and interactive elements), prototyping platforms, copywriting, SEO, site analytics, and front-end frameworks. A good UI developer knows HTML, CSS, and—though it’s not mandatory—Photoshop.

Q: Name three ways to reduce a page’s load time.

A: Eliminate unnecessary widgets, minimize redirects, and reduce image sizes.

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Q: What is HTML?

A: HTML is the most popular language for creating websites, as well as any elements viewed in a web browser. It stands for HyperText Markup Language.

Q: What is Semantic HTML?

A: Also known as semantic markup, it’s HTML that uses tags to embody what the text is trying to convey. In other words, it brings meaning and a presentation to a webpage.

Q: Name at least three position property attributes.

A: Property attributes include absolute, fixed, inherit, relative, and static.

Intermediate Questions

Q: Explain the difference between the <b> and <strong> tags.

A: The <b> tag is a presentational element that only displays text in bold, while <strong> also assigns substantial importance to the text regarding search results.

Q: Discuss the differences between this quartet of position properties: Relative, Absolute, Static, and Fixed.

A: Relative moves an element concerning its current position. Absolute moves an element concerning its current position or the parent element’s position. Absolute elements don’t occupy space in DOM flow. Static is the default position. Fixed gives an element a fixed position relative to the device screen. None of these elements move during scrolling.

Q: Explain web accessibility.

A:  Web accessibility provides website access for differently-abled and disabled persons so that they can easily understand, navigate, and interact with the web.

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Q: What is JavaScript Hoisting?

A:  Hoisting is a mechanism where assigned variables and function declarations get moved or “hoisted” to the top of their scope before executing code. Therefore, no matter where functions and variables are declared, they get moved to the top of their range regardless of whether their scope is local or global.

Q: What’s the difference between HTML and XHTML?

A: Although both languages create web pages, HTML is a hypertext markup language, whereas XHTML is an extensible hypertext markup language. XHTML is XML based, while HTML is SGML based. XHTML is strict compared to HTML and doesn’t allow users to get away with any coding or structure lapses.

Q: Explain the differences between local storage, session storage, and cookies.

A:  These can be explained as follows:   

  • Local storage allows data storage with no expiration date and offers the most substantial maximum storage limit.
  • Session storage stores the data associated with a session. When the user closes the tab or browser, the data disappears.
  • Cookies are reserved mostly for server-side reading, storing data sent back to the server. The data size must be less than 4KB.

Q: Discuss the differences between a document and a window.

A:  A window object has properties such as inner width, inner height, length, whether it was previously closed, its parent, and its name. The window is the first thing loaded into the browser.  The document object is defined as any document that gets loaded inside the window object, such as HTML, ASPX, or PHP, and has properties such as cookies, title, and URL, to name a few.

Q: Does HTML require a compiler?

A: Since it’s a front-end language, HTML doesn’t need a compiler. However, languages such as C, C++, and Java require a compiler to convert the code into a language that a machine can comprehend.

Advanced Questions

Q: How do floats work?

A:  Floats push the element to the left or right. The float property can have one of four values:

  • Inherited: The element inherits the parent’s float value
  • None: This is the default value; the element doesn’t float
  • Left: The element floats to the container’s left
  • Right: The element floats to the container’s right

Q: Name at least three plugins available in the Bootstrap jQuery plugin library.

A:   Answers include:

  • Alert
  • Affix
  • Button
  • Carousel
  • Collapse
  • Dropdown
  • Modal
  • Popover
  • Scrollspy
  • Tab
  • Tooltip

Q: Using the latest version of Bootstrap, what CSS class do you employ to span 14 columns on medium-sized screens, and eight columns on large screens?

A:  class=”col-md-14 col-lg-8”

Q: How do you verify whether or not a variable is set In PHP?

A: Use this command: !isset($var);

Q: When you encounter an error, what’s the difference between require() and include()?

A: The command includes () raises a warning if it fails while requiring () raises a fatal error.

Q: What is a CSS reset, and how does it differ from normalize.css?

A: Reset.css eliminates all browser default styles, such as margin, padding, and border. Normalize.css sets a standard book-like appearance (e.g., bold headings, margins between two paragraphs, common font) across all browsers. However, it doesn’t reset them.

Q: What’s an AJAX request, and how would an AJAX request be used?

A: AJAX is an acronym for asynchronous JavaScript and XML and is a client-side process written in JavaScript. It is used to get or post data from a remote server without needing to reload the page.

Q: How do you use HTML5 new tags in IE version eight and earlier?

A: That’s a trick question, because HTML5 semantic tags like the article, figcaption, footer, header, nav, and section, are not supported by HTML4-based browsers, and that includes IE8. However, you can use html5shiv.js to run these elements in the older browsers.

Take the Next Step Toward Becoming a UI Developer

Interview question and answer refreshers are great, but nothing beats right, solid information and skills taught in a professional yet relaxed environment. Whether you’re looking to become a UI developer or want to boost your existing UI skills, Simplilearn has everything you need.

Simplilearn’s Design Training Courses help you to master all of the critical elements required to design great products, everything from understanding customer needs to developing compelling user interfaces.

The Design Thinking Certification Training Course helps you master the robust process of problem-solving that involves understanding customer needs on a deeper level. You'll learn Simplilearn’s patented 5D Design Thinking Framework, get aligned with industry standards, frame design problems, and validate innovative solutions. You’ll become an expert in business strategy and innovation and with it, the confidence and know-how to drive a design thinking culture in your organization.

The Visual Design Training Course gives you a broad introduction to the art of building engaging user interfaces for your software products. You will learn how to enhance the look, feel, and general aesthetics of your designs to make them more appealing for end-users. And you’ll master the use of color, space, shapes, typography, and form to forge more meaningful and impactful visual connections that will enhance usability and improve the user experience.

The User Experience (UX) Interaction Design Training Course teaches you the customer-oriented and prototype-driven process of creating efficient interactions between users and an interface. You’ll develop a deep understanding of usability principles, user needs, and design best practices to add more meaning to your products, define a compelling user journey, and give your audience an unforgettable user experience.

Finally, the User Experience (UX) Research Training Course introduces you to the vital process of researching user preferences to design and build better products. You will learn how to gather extensive information on user behavior, map user journeys, and analyze competitive products to generate a compelling user experience. This course will train you to understand better how customers react when they use your products.

Check out Simplilearn today and join this fast-growing, rewarding IT career!

About the Author


Simplilearn is one of the world’s leading providers of online training for Digital Marketing, Cloud Computing, Project Management, Data Science, IT, Software Development, and many other emerging technologies.

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  • PMP, PMI, PMBOK, CAPM, PgMP, PfMP, ACP, PBA, RMP, SP, and OPM3 are registered marks of the Project Management Institute, Inc.
  • *According to Simplilearn survey conducted and subject to terms & conditions with Ernst & Young LLP (EY) as Process Advisors