Helpshift Interview Questions and Answers

Event mechanism in JavaScript allows elements to trigger actions based on user interaction or system events.

• Events are actions or occurrences that happen in the browser, such as a user clicking a button or the page finishing loading.

• Event listeners are functions that are triggered when an event occurs on a specific element.

• Events can be attached to elements using the addEventListener() method.

• Events can also be trigger...read more

Event bubbling and capturing are two ways of propagating events in the DOM tree.

• Event capturing is the process of triggering the outermost element's event first and then moving towards the innermost element.

• Event bubbling is the process of triggering the innermost element's event first and then moving towards the outermost element.

• Event capturing is rarely used in practice, while event bubbling is the default behavior ...read more

Async and defer attributes are used in HTML script tags to control when and how scripts are loaded and executed.

• Async attribute allows the script to be downloaded asynchronously without blocking the HTML parsing.

• Defer attribute defers the script execution until the HTML parsing is complete.

• Async scripts can be executed out of order, while defer scripts are executed in the order they appear in the HTML.

Browsers render HTML, CSS, and JavaScript to display web pages.

• Browser sends a request to the server for a web page

• Server sends back HTML, CSS, and JavaScript files

• Browser parses HTML to create the Document Object Model (DOM)

• Browser applies CSS to the DOM to create the Render Object Model (ROM)

• JavaScript is executed and can modify the DOM and ROM

• Browser displays the final web page

Browsers parse HTML, CSS, and JavaScript to render content on the screen.

• Browsers read HTML from top to bottom and left to right.

• They construct the Document Object Model (DOM) tree based on the HTML structure.

• CSS is then applied to the DOM tree to style the content.

• JavaScript is executed to add interactivity and manipulate the DOM.

• Finally, the browser renders the content on the screen.