Javascript cheatsheet for beginners

IF-ELSE STATEMENTS –

if (condition) {

//what to do if condition is met

}

else{

//what to do if condition is not met

}

STRINGS-

var person = “John Doe”;

ESCAPE CHARACTERS:

\’   -Single quote

\”   -Double quote

\\   – Backslash

\b  – Backspace

\t   – Horizontal tabulator

\n   -New line

STRING METHODS-

• charAt() – Returns a character at a specified position inside a string

• charCodeAt() – Gives you the unicode of character at that position

• concat() – Concatenates (joins) two or more strings into one

• fromCharCode() – Returns a string created from the specified sequence of   UTF-16 code units 

• indexOf() – Provides the position of the first occurrence of a specified text  within a string

• lastindexOf() – Same as indexOf() but with the last occurrence, searching backwards

• match() – Retrieves the matches of a string against a search pattern

• replace() – Find and replace specific text in a string

• search() – Executes a search for a matching text and returns its position

• slice()- Extracts a section of a string and returns ft as a neW string

• split()- Splits a string object into an array of strings at a specified position

• substr() – Similar to slice() but extracts a substring depended on a  specified number of characters

• substring() – Also similar to slice) but can’t accept negative indices

• toUpperCase() – Convert strings to uppercase

• valueOf() – Returns the primitive value (that has no properties or methods) of a string object

GLOBAL FUNCTIONS –

• decodeURI() – Decodes a Uniform Resource identifier (URI)  created by encodeURI or similar

• decodeURIComponent() – Decodes a URI component

• encodeURI()- Encodes a URI into UTF-8

• encodeURIComponent() – Same but for URI components 

• eval()- Evaluates JavaScript code represented as a string 

• isFinite() – Determines whether a passed value is a finite number

• isNaN()- Determines whether a value is NaN or not

LOOPS –

for (before loop; condition for loop; execute after loop) {// what to do during the loop }

• for –The most common way to create a loop in Javascript

• while – Sets up conditions under which a loop executes

• do while – Similar to the while loop, however, it executes at least  once and performs a check at the end to see if the condition is met to execute again

• break – Used to stop and exit the cycle at certain conditions

• continue – Skip parts of the cycle if certain conditions are met

EVENTS –

Mouse:

• onclick- The event occurs when the user clicks on an element

• oncontextmenu – User right-clicks on an element to open a context menu

• ondblclick – The user double-clicks on an element

• onmousedown – User presses a mouse button over an element

• onmouseenter – The pointer moves onto an element

• onmouseleave – Pointer moves out of an element

• onmousemove- The pointer is moving while it is over an element

• onmouseover- When the pointer is moved onto an element or one of its children

• onmouseout – User moves the mouse pointer out of an element or one of its children

• onmouseup –  The user releases a mouse button while over an element

Keyboard:

• onkeydown- When the user is pressing a key down

• onkeypress – The moment the user starts pressing a key

• onkeyup –  The user releases a key

Form:

• onblur- When an element loses focus

• onchange- The content of a form element changes (for <input>, <select>and <textarea>)

• onfocus – An element gets focus

• onfocusin – When an element is about to get focus

• onfocusout – The element is about to lose focus

• oninput- User input on an element

• oninvalid – An element is invalid

• onreset –  A form is reset

• onsearch – The user writes something in a search field (for <input=”search”>)

• onsubmit – A form is submitted