JavaScript Language | 30 Minute Test 9

If the script tag is placed after the body tag, then, it will not be evaluated at all. Also, it is always recommended and effective to use the script snippet in the tag.

Generally, X or x denotes hexadecimal values. So, any integer literal that begins with 0X or 0x denotes a hexadecimal number.

The simplest expressions, known as primary expressions, are those that stand alone — they do not include any simpler expressions. Primary expressions in JavaScript are constant or literal values, certain laguage keywords, and variable references.

A conditional expression can evaluate to either True or False based on the wvaluation of the condition.

The above code uses a for loop to traverse a linked list data structure and return the last object in the list. This will perfectly work.

firstname and surname are the property names. The value of that particular property is itself an object. That is why these property names are unquoted.

Arrays have a pop() method (it works with push()) that reduces the length of an array by 1 but also returns the value of the deleted element.

The function name is optional for functions defined as expressions. A function declaration statement actually declares a variable and assigns a function object to it.

Function name is optional for functions defined as expressions. Function expressions are sometimes defined and immediately invoked.

A combination of a function object and a scope (a set of variable bindings) in which the function’s variables are resolved is called a closure.

The result is true: the constructor property specifies the class.

The properties of the prototype object are inhertied by all instances of the class, and properties whose values are functions behave like instance methods of the class.

A programmer can import frequently used values into the global namespace. A programmer who was going to make frequent use of the Set class from the sets namespace might import the class like that.

The [^…] character class is used to match or draw any one character not between the brackets.

Each subset is coupled with a static verifier that parses code to ensure that it conforms to the subset.

Variables declared with var are defined throughout the enclosing function. Variables declared with let are defined only within the closest enclosing block (and any blocks nested within it, of course).

If a catch clause has no conditional, it behaves as if it has the conditional if true, and it is always triggered if no clause before it was triggered.

The removeAllListeners(name) is used to remove all handlers from name events represented as :
emitter.removeAllListeners(name)

Rhino defines a handful of important global functions that are not part of core JavaScript in which readUrl(url) reads the textual contents of a URL and return as a string.

The node programs can be run with the command:
node program.js

Microsoft implements its own proprietary client-side storage mechanism, known as “userData,” in IE5 and later. userData enables the storage of medium amounts of string data and can be used as an alternative to Web Storage in versions of IE before IE8.

If your JavaScript code contains the < or & characters, these characters are interpreted as XML markup.

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.

The Prototype library focuses on DOM and Ajax utilities like jQuery does, and adds quite a few core-language utilities as well.

The onerror handler method can be registered to be invoked when uncaught JavaScript exceptions occur.

The various properties of the location object are the protocol, host, hostname, port, search, and hash.

The length property of the History object specifies the number of elements in the browsing history list, but for security reasons scripts are not allowed to access the stored URLs.

Client-side JavaScript makes very little distinction between windows, tabs, iframes, and frames: they are all browsing contexts, and to JavaScript, they are all Window objects.

The node directly above a node is the parent of that node.