Basic syntax for JavaScript

One: Basic data types:

String, Decimal, Integer, DateTime, Boolean

Two: Variables

are generic type Var, can store other types of values, can be used directly, not defined, but is customary to define.

Define variables: var A: All variable definitions are defined with Var, var is a generic mutable type.

Three: type conversion

It is divided into automatic conversion and casting, which is generally used for casting.

Other types converted to integers: parseint ();

Other types converted to decimals: parsefloat ();

In addition to determine whether it is a valid number type: IsNaN ();

Four: operator

Math operator: +-/% + +-;

Relational operators: = =! = >=< <=;

Logical operator:&& | | !;

Five: statement

Generally divided into sequential, branching and looping statements

(1) Branch if statement

if (judging condition) {The statement that satisfies the condition to be executed}else{the statement that the condition is to be executed}

　　

(2) Loop for statement

for (initial condition; cyclic condition; state change) (loop body)

　　

VI: Array

Definition of the array: the new Array (); his length is dynamic, which can be placed in any type of element.

Assignment of array elements: a[0]=123; A[1]= "";

Array value: A[i]:

Array properties: A.length: Number of array elements, length.

Seven: Functions

The function in JS is the same as the four elements in C #.

Define functions: Function ... () {function Body}, ... As the function name, the input is the form of a parameter, and the return value can be either a var type or a return value.

Functions that do not call are not executed.

Basic syntax for JavaScript