A signup form on a coffee shop’s site, Grounded, uses if (age >= 65) { tier = ‘Senior’; } else if (age >= 18) { tier = ‘Adult’; } else if (age >= 13) { tier = ‘Teen’; }. For a visitor whose age is 70, how many of these branches actually execute?

A volunteer matching site called HelpDesk Civic has a checkbox labeled “I can drive volunteers to events,” and code that should run only once, right when the box gets checked or unchecked — not repeatedly during any other interaction with the page. Which event best matches “only once, right when the box’s checked state actually flips”?

A ticket booking site, StageDoor, has a form with a text field for a promo code and a checkbox for “Sign me up for email deals.” Based on the quick reference table, which property should be read for each, respectively, to get the intended data type?

A weather dashboard, SkyCast, wants a –sky-opacity custom property set from a slider, and the CSS expects a percentage string like “40%”, not a bare number. Following this exact pattern for appending units, how should the slider’s raw value be prepared before being passed to setProperty?

A signup form on a used bike marketplace, SpokeSwap, has if (!name) { showError(‘Name is required’); }, functionally equivalent to writing if (name === ”) { … } per the deck. If name currently holds the value “0” (a string typed by someone entering a nickname), does !name trigger the error?

A checklist app, Taskly, needs logic that, for a completed task, both strikes through its text AND moves it to a “Done” section — two separate actions — while for an incomplete task it does nothing extra at all. Based on this guidance, is a ternary or an if/else the better structural fit?

A habit tracker, Streaky, has three checkboxes for daily habits: “Drink water,” “Stretch,” and “Read.” A developer logs checkbox.value for each one after the user interacts with the page. What will these three console.log calls print, regardless of which boxes are actually checked?

A language-learning app called Lingo Loop wants a password field to show a live strength meter that updates the instant the user types or deletes a character, before they move to the next field. Between input and change, which one satisfies “updates the instant” the character changes, and why?

The medical term for excessive thirst is a symptom of diabetes mellitus:

A genetic disease that causes thick, sticky mucus to build up in the lungs and other organs is: