JavaScript Language | 30 Minute Test 8

A Live Wire database driver also supports a number of non-relational databases.

The variables whose values can be changed are called mutable variable types.

a function definition expression is a “function literal” in the same way that an object initializer is an “object literal.” A Function definition expression typically consists of the keyword function followed by a comma-separated list of zero or more identifiers (the parameter names) in parentheses and a block of JavaScript code (the function body) in curly braces.

The interpreter checks obj for property b, fails and takes it from outside of with.

In a for loop, the initialization, the test, and the update are the three crucial manipulations of a loop variable.

Every object has three associated object attributes :
An object’s prototype is a reference to another object from which properties are inherited.
An object’s class is a string that caegorizes the type of an object.
An object’s extensible flag specifies whether new properties may be added to the object.

a1 has an element with index 0 and a2 has no element with index 0.

The above code snippet returns undefined.

None.

In order to implement lexical scoping, the internal state of a JavaScript function object must include not only the code of the function but also a reference to the current scope chain.

The ‘this’ keyword is used to refer to the object through which the properties or methods were invoked. This use of ‘this’ is a fundamental characteristic of the methods of any class.

In JavaScript, there are three different objects involved inany class definition, and the properties of these three objects act like different kinds of class members namely, Constructor object, Prototype object, and Instance object.

Generally, the various modules are allowed to run in the pristine (or near pristine) environment that it expects. The modules should minimize the number of global symbols they define – ideally, no module should define more than one.

The given pattern is applied on the text given in the paranthesis.

The subset does not include the comma operator, the bitwise operators, or the ++ and — operators. It also disallows == and != because of the type conversion they perform, requiring use of === and !== instead.

The let keyword can be used in four ways :
1.as a variable declaration like var;
2.in a for or for/in loop, as a substitute for var;
3.as a block statement, to define new variables and explicitly delimit their scope; and
4.to define variables that are scoped to a single expression.

The above code snippet sorts an array in reverse numerical order.

The removeListeners(name,f) is used to deregister event handler f represented as :
emitter.removeListener(name,f)

The spawn(f) runs f() or loads and executes file f in a new thread.

Because the APIs are asynchronous, Node relies on event handlers, which are often implemented using nested functions and closures.

HTML5 defines an “Offline Web Applications” API that allows the caching of web pages and their associated resources (scripts, CSS files, images, and so on). This is client-side storage for web applications themselves rather than just their data, and it allows web apps to install themselves so that they are available even when there is no connection to the Internet.

JavaScript code can appear inline within an HTML file between the “script” tags.

The Window object is the main entry point to all client-side JavaScript features and APIs. It represents a web browser window or frame, and you can refer to it with the identifier window.

Each Element object has style and className properties that allow scripts to specify CSS styles for a document element or to alter the CSS class names that apply to the element.

One of the most popular frameworks is jQuery. Here, JavaScript is a scripting language and not a framework.

setTimeout() and setInterval() allow you to register a function to be invoked once or repeatedly after a specified amount of time has elapsed.

The location property of a window is a reference to a Location object; it represents the current URL of the document being displayed in that window.

If a window contains child windows, the browsing histories of the child windows are chronologically interleaved with the history of the main window.

HTML documents may contain nested documents using an iframe element. An iframe creates a nested browsing context represented by a Window object of its own.

The paragraph tag belongs to both html and body tags.