INF-306 Certification Exam Guide + Practice Questions Updated 2026

Explanation:
The correct selections are C and D because both declare a function as a property of an object, which is the defining characteristic of a JavaScript method. MDN describes a method as a function associated with an object, or more specifically, an object property whose value is a function. In option C, Score: function() { ... } is object-literal syntax. It defines a property named Score whose value is an executable function, so that property behaves as a method of the object. In option D, this.Score = function() { ... } assigns a function to the Score property of the current object instance. MDN notes that this is commonly used inside object methods to refer to the object the method is attached to.
Option B does not declare a method; it calls Score() and assigns the return value.
Option A is only an incomplete or ordinary variable declaration and does not create a function-valued object property.
References/topics: JavaScript objects, custom classes, methods, function expressions, this.

Explanation:
The value stored in num is the number of key-value pairs currently stored in localStorage. The localStorage object implements the Web Storage Storage interface, which stores data as named string key/value entries for the current origin. Its length property is read-only and returns the number of data items stored in that Storage object, not the size of the stored data and not the remaining capacity. MDN’s Storage reference explicitly defines length as returning the number of data items stored, and its example shows that after three items are added to localStorage, localStorage.length returns 3. Therefore, if the storage area contains five named entries, num receives 5; if it contains no entries, num receives 0.
Option A is incorrect because available bytes are not exposed through length.
Option B is unrelated to Web Storage.
Option C is incorrect because browser storage quota or capacity is separate from the length property.
References/topics: Web Storage API, localStorage, Storage.length, key-value storage, application state.

Explanation:
First drop-down: var xhr = new XMLHttpRequest();
Second drop-down: if(xhr.status===200){
Third drop-down: responseObject = JSON.parse(xhr.responseText);
The script must first create an XMLHttpRequest object, so the correct first selection is var xhr = new XMLHttpRequest();. This object performs the asynchronous request for menu.json. After the request finishes, the onload callback executes. The response should be processed only when the request succeeds, so the correct status check is if(xhr.status===200){; HTTP status 200 means the file was successfully retrieved. Status codes 403, 404, and 500 represent forbidden access, missing resource, and server error conditions, so they are not appropriate for normal JSON processing. The JSON file is returned as plain text through xhr. responseText, so it must be converted into a JavaScript object with JSON.parse(xhr.responseText). Once parsed, the code can access responseObject.menu[i].Entree, Price, and Description inside the loop and build the display output. responseXML is incorrect because the source file is JSON, not XML.

Explanation:
The correct setting is overflow: auto;. The requirement is precise: the text must remain inside the element’s border, must not be lost, and scrollbars should not appear unless they are needed. overflow: auto satisfies all three requirements because it clips overflowing content to the element’s box and creates scrollbars only when the content actually exceeds the available space. This preserves access to all text while avoiding unnecessary horizontal or vertical scrollbars when the content fits. overflow: hidden is incorrect because it clips the overflowing text and provides no scrolling mechanism, meaning some content may become inaccessible. overflow: visible is incorrect because the extra text can flow outside the element boundary, violating the requirement to keep content inside the border. overflow: scroll is close but not optimal because it forces scrollbars even when they are not required, which directly conflicts with the instruction to avoid unneeded scrollbars.
References/topics: CSS overflow, scroll containers, text containment, content clipping, layout flow.

Explanation:



The correct markup uses the HTML5 < datalist > element because the interface shows a text input with a drop-down list of suggested values. The < input > element has list= " vehicles ", which means it must be connected to a < datalist > whose id value is exactly vehicles. This relationship is essential: the list attribute on the input references the id of the datalist that supplies the available options. Each < option > element inside the datalist defines one suggested value: Motorcycle, Truck, Boat, Car, and Bicycle. Unlike a traditional < select > element, a datalist does not restrict the user only to the listed choices; the user can either select an option with the mouse or type directly into the input field. That behavior matches the displayed interface, where the control appears as an editable text box with suggestions. The final closing tag must be < /datalist > because the option elements belong to the datalist container.
References/topics: HTML5 forms, < input list >, < datalist >, option elements, selectable typed input.