Awesome JavaScript Reference

Awesome JavaScript


JavaScript Glossary of Terms

Ajax- "(asynchronous JavaScript and XML)" – set
of web development techniques using
many web technologies
on the client-side to create asynchronous
Web applications.With Ajax, web
applications can send data
to and retrieve from a server asynchronously
(in the background) without interfering
with the display and
behavior of the existing page.

Algorithm- set of computer instructions
to produce an output
or end state from an input
or beginning state. What programs
are made of.

Arity-     refers to the number of arguments
an operator takes.
ex: a binary function
takes two arguments

Attribute- An attribute is a modifier
of an element type.

Bookmarklet- technique of saving
JavaScript within a bookmark
or hyperlink, so that it can
be executed by clicking on it.
In many cases, the link can be dragged
and dropped to the browser
toolbar for easier access.

Chai­ning-     also known as casca­ding,
refers to repeatedly calling
one method
after another on an object, in one
continuous line of code.

Curr­ying-    refers to the process of
transf­orming a function with
multiple arity into the
same function with less arity

DRY-     Don't Repeat Yourself

Document Object Model- (DOM) the
hierarchy (tree) produced
by the browser of all the
elements of a webpage. By processing the DOM
via "methods" (functions stored as object
properties, that is, the actions
that can be performed
on objects), JavaScript can dynamically
change the page's HTML.

ECMAScript- the specification language upon
which JavaScript is based. The terms
"EMCAScript" and "JavaScript" are used
interchangeably within the field.
'ES' has also been
used as a prefix for shorthand names
of versions of JavaScript.

Event- action or occurrence recognized by
software, often originating asynchronously from
the external environment, that may be handled
by the software. Computer events can be
generated or triggered by the system, by the
user (via keystrokes or a mouse clicks),
or in other ways.

Event-driven programming- software
that changes its
behavior in response to events is
said to be event-driven, often with the
goal of being interactive.

First-class function- the functions
of a language are
first-class functions if they are
first-class objects.
The functions in JavaScript
are first-class objects,
and therefore, first-class functions.

First-class object- entity which supports all the
operations generally available to other
entities (such as data types). These operations
typically include being passed as an argument,
returned from a function, modified, and assigned
to a variable. In JavaScript, functions are
first-class objects.

Higher Order Functi­ons-    functions that accept
other functions as an argument

JSON- stands for JavaScript Object Notation,
an open-standard file format that uses
human-readable text to transmit data objects
consisting of attribute–value pairs and array
data types (or any other serializable value).
It is a very common data format used for
asynchronous browser–server communication,
including as a replacement for XML in
some AJAX-style systems.

Pred­icate-     a calcul­ation or other operation
that would evaluate either to "­tru­e" or “false.”

Recu­rsion-     an approach in which
a function calls itself

Scope-     the set of variables, objects, and
functions available within a
certain block of code

var- The most common variable. Can be
reassigned but only accessed within a function.
Variables defined with var move to the top
when the code is executed.

const- Can not be reassigned
and not accessible
before they appear within the code.

let- Similar to const, the let variable can be
reassigned but not re-declared.

Objects- Certain kind of variables. They are
variables which can have
their own values and methods.

concat()- Join several arrays into one

indexOf()- Returns the primitive
value of the specified object

join()- Combine elements of an array into a
single string and return the string

lastIndexOf()- Gives the last position at which
a given element appears in an array

pop()- Removes the last element of an array

push()- Add a new element at the end

reverse()- Sort elements in a descending order

shift()- Remove the first element of an array

slice()- Pulls a copy of a portion
of an array into a new array

sort()- Sorts elements alphabetically

splice()- Adds elements in a
specified way and position

toString()- Converts elements to strings

unshift()- Adds a new element to the beginning

valueOf()- Returns the first position at which a
given element appears in an array

alert()- Output data in an alert box in the browser window

confirm() - Opens up a yes/no dialog and
returns true/false depending on user click

console.log()- Writes information to the
browser console, good for debugging purposes

document.write()- Write directly
to the HTML document

prompt()- Creates a dialogue for user input

Basic Operators

+ -Addition

- - Subtraction

     *  - Multiplication

     /  - Division

  (...)    - Grouping operator, operations within
brackets are executed
earlier than those outside    

   %  - Modulus (remainder )

   ++  - Increment numbers

    --  - Decrement numbers

Comparison Operators

== - Equal to

=== - Equal value and equal type

!= - Not equal

!== - Not equal value or not equal type

> - Greater than

< - Less than

>= - Greater than or equal to

<= - Less than or equal to

Logical Operators

&& - Logical and

|| - Logical or

! - Logical not

Bitwise Operators

& - AND statement

| - OR statement

~ - NOT

^ - XOR

<< - Left shift

>> - Right shift

>>> - Zero fill right shift

String Object Methods

returns the character at the specified index
joins two or more strings, and
returns a copy of the joined strings
returns the position of the first found
occurence of a specified value in a string
returns the position of the last found
occurence of a specified value in a string
searches for a match between a
substring (or regex) and a string, and
replaces the matched substring
with a new substring
searches for a match between a regex
and a string, and returns the
position of the match
extracts a part of a string and returns
a new string
splits a string into an array of substrings
extracts the characters from a string,
beginning at a specified start position,
and through the specified number of character
extracts the characters from a string,
between two specified indices
converts a string to lowercase letters
converts a string to uppercase letters
removes whitespace from both ends of a string
returns the primitive value of a String object
returns the value of a String object

Math Object Methods

returns the absolute value of x
rounds x to the nearest integer
returns x, upwards to the nearest integer
returns x, rounded downwards to the nearest integer
returns the value of Ex
returns the narural logarithm (base E) of x
max(x, y, z, ...)
returns the number with the highest value
min(x, y, z, ...)
returns the number with the lowest value
pow(x, y)
returns the value of x to the power of y (xy)
returns the square root of x
returns a random number between 0 and 1
returns the sine of x (x in radians)
returns the cosine of x (x in radians)
returns the tangent of an x

Event handlers

onAbort loading stopped

onBlur focus lost

onChange content modified

onClick clicked

onDblClick clicked twice

onDragDrop moved

onError not loaded

onFocus focus entered

onKeyDown key depressed

onKeyPress key pressed

onKeyUp key released

onLoad just after loading

onMouseDown mouse button depressed

onMouseMove mouse moved

onMouseOut mouse exited

onMouseOver mouse on the element

onMouseUp mouse button released

onReset reset form button clicked

onResize size of page changed

onSelect element selected

onSubmit submit form button clicked

onUnload page exited

Accessing DOM Elements

document.getElementById(id); -  Returns
a reference to the element by its ID.

document.getElementsByClassName(names); -  
Returns an array-like object of all child elements
which have all of the given class names.

document.getElementsByTagName(name); -  
Returns an HTMLCollection of elements with the
given tag name.

document.querySelector(selectors); -  
Returns the first element within the document that matches
the specified group of selectors.

document.querySelectorAll(selectors); -  
Returns a list of the elements within the document
(using depth-first pre-order traversal of the
document's nodes) that match the specified group
of selectors.


// Single-line comments start with two slashes.

/* Multiline comments start with slash-star,
  and end with star-slash */


<button onclick="myFunction();">
  Click here


onclick, oncontextmenu, ondblclick,
onmousedown, onmouseenter, onmouseleave,
onmousemove, onmouseover, onmouseout, onmouseup


onkeydown, onkeypress, onkeyup


onabort, onbeforeunload, onerror,
onhashchange, onload, onpageshow, onpagehide,
onresize, onscroll, onunload


onblur, onchange, onfocus, onfocusin,
onfocusout, oninput, oninvalid,
onreset, onsearch,
onselect, onsubmit


ondrag, ondragend, ondragenter,
ondragleave, ondragover, ondragstart, ondrop


oncopy, oncut, onpaste


onabort, oncanplay, oncanplaythrough,
ondurationchange, onended, onerror, onloadeddata,
onloadedmetadata, onloadstart, onpause,
onplay, onplaying, onprogress, onratechange,
onseeked, onseeking, onstalled, onsuspend,
ontimeupdate, onvolumechange, onwaiting


animationend, animationiteration, animationstart


transitionend, onmessage, onmousewheel,
ononline, onoffline, onpopstate, onshow, onstorage,
ontoggle, onwheel, ontouchcancel, ontouchend,
ontouchmove, ontouchstart

Global Functions

eval();                     - executes a string as if it was script code

String(16);                 - return string from number

(16).toString();            - return string from number

Number("16");               - return number from string

decodeURI(enc);             - decode URI. Result: "my page.asp"

encodeURI(uri);             - encode URI. Result: "my%page.asp"

decodeURIComponent(enc);    - decode a URI component

encodeURIComponent(uri);    - encode a URI component

isFinite();                 - is variable a finite, legal number

isNaN();                   - is variable an illegal number

parseFloat();               - returns floating point number of string

parseInt();                 - parses a string and returns an integer

Reserved Keywords

abstract   else   instanceof   super  
boolean   enum   int   switch  
break      export   interface   synchronized  
byte          extends   let   this  
case   false   long   throw  
catch   final   native   throws  
char   finally   new   transient  
class   float   null   true  
const   for   package   try  
continue   function   private   typeof  
debugger   goto   protected   var  
default   if   public   void  
delete   implements   return   volatile  
do   import   short   while  
double   in   static   with


alert   frames   outerHeight  
all   frameRate   outerWidth  
anchor   function packages  
anchors   getClass   pageXOffset  
area   hasOwnProperty   pageYOffset  
Array   hidden   parent  
assign   history   parseFloat  
blur   image   parseInt  
button   images   password  
checkbox   Infinity   pkcs11  
clearInterval   isFinite   plugin  
clearTimeout   isNaN   prompt  
clientInformation   isPrototypeOf   propertyIsEnum  
close   java   prototype  
closed   JavaArray   radio  
confirm   JavaClass   reset  
constructor   JavaObject   screenX  
crypto   JavaPackage   screenY  
Date   innerHeight   scroll  
decodeURI   innerWidth   secure  
decodeURIComponent   layer   select  
defaultStatus   layers   self  
document   length   setInterval  
element   link   setTimeout  
elements   location   status  
embed   Math   String  
embeds   mimeTypes   submit  
encodeURI   name   taint  
encodeURIComponent   NaN   text  
escape   navigate   textarea  
eval   navigator   top  
event   Number   toString  
fileUpload   Object   undefined  
focus   offscreenBuffering   unescape  
form   open   untaint  
forms   opener   valueOf  
frame   option   window  

Additional Handlers

onbeforeunload   ondragdrop   onkeyup   onmouseover  
onblur   onerror   onload   onmouseup  
ondragdrop   onfocus   onmousedown   onreset  
onclick   onkeydown   onmousemove   onsubmit  
oncontextmenu   onkeypress   onmouseout   onunload


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