A summary of JavaScript and PHP essentials

J S Essentials Overview including:

Variable:

Define a container, store content inside

Global variables: Variables outside the scope

Local variables: Within the scope

Data type: base data type and reference data type

Basic:undefined,null,Boolean,number(int/float) and the string ;

Reference:object,array,data

Operator:

Arithmetic operators:

+ + in front: Calculates the return value first

+ + in the back: first return value and then calculate

Comparison operators:

>,>=,<,<=,!=,== ( Comparison of Values ), = = = ( values and types are compared ),!==

Logical operators:

&& | | They result in the number of one of the operations

|| Short Circuit Operation

Note: As long as the previous result is true, then the result is not important; on the contrary, once it is false, the back is meaningless.

! Take a non-boolean result usage: When judging and when establishing an identity

string Operator:+

Control statements:

If ElseIf Switch

Loop structure:

while () do{} and for ()

An expression:

if{

}else{

}

If ( judging condition ) {

}else if () {

}

Switch () {

Case Expression :

Branch ;

Case Expression:

Branch ;

}

Key words:

Break: Jump out of the current page of this layer loop

Continue: Jumps out of the current loop to the next loop

Array:

A container where a set of data is filled

Statement:

Var arr = [ element 1 ...];

Var arr = new Array ( element 1 ...);

array Lengths:length

Array Traversal:

for (var i = 0;i< judging condition;i++) {

}

For (Var A in arr) {

}

Function:

to be declared after a call; written in the script tag .

function function name () {

}

Assignment function declaration: NOTE: no " preload " must be declared before calling

Var function name = function () {

}

Function arguments: formal parameters and arguments

return value:return

Function call:

Name of function ();

Anonymous functions:

(function () {

})();

usage of Eval:

Eval () receives the string and calculates the result inside

PHP Essentials are summarized as follows:

Variable:

"$" symbol

Variable name refers to the corresponding value

Value passing:

Procedure for value passing: passing a value to another variable

Reference delivery:

The passing of a reference relationship: One result is changed, the other results are changed.

mutable variable: It is a variable in itself and can also be used as another variable

pre-defined variables: fixed variables such as:

$get: A link /<form action= "Jump page" method= "get" > form content </form>

$post:<form action= "Jump page" method= "post" > form content </form>

$request: All of the data collection that is sent (committed) by Get and post.

$_server:

Data type:

scalar type: int(integer), float(decimal), string(String) , bool(Boolean)

Composite type: array(array), object

Special type: null(null value), Resource(Resource)

type of array:array

Type: Object

Operator:

Arithmetic operators:

+ - * / % ++ --

Note: take the remainder operation %, take the whole first, then take the remainder

Self-increment decrement operator:

$a + +;

Boolean Increment decrement invalid

Null decrement is invalid, increment result is 1

Front + +: Calculate first and then do something else

Post + +: Store and calculate first

Comparison operators:

> < >= < <= = = Data Equal = = Unequal = = = value and type must be equal!==

Logical operators:

&& | | or! Non-

|| Attention Short Circuit

String operators:

./ .=

Assignment operators:

= += -= *= /= %= .=

Three-mesh operators:

form: Data 1 ? Data 2 : Data 3;

Control statements:

For Loop :

foreach (var $arr as $k = = $v) {

}

Array :

$arr 1 = Array ( element 1, Element 2, ...). );

Associative arrays: Arrays that are labeled as strings

Indexed arrays: arrays labeled as numbers

Array Traversal:

foreach ($arr as [$key = =] $value)//$key is a key,$value is a value variable.

{

Function:

function function name ( parameter 1, parameter 2,...)

{

Formal parameter (variable name), argument (actual data)

There is usually a " one by one correspondence " relationship between an argument and a parameter in PHP:

function function name ( parameter 1, parameter 2,...)

{

Invocation form: function name (argument 1, argument 2,... ) )

Default value parameter: is to give the parameter a default value, use the time directly with the default value

A summary of JavaScript and PHP essentials