Python full stack development day44-js, DOM, BOM

JS three parts of one, Ecmajavascript basic syntax: 1.javascript introduction 1) Inline

<script>

Alert (1)

</script>

2) Introduction Type

<script src= ' test.js ' > </script>

2.javascript Basic Syntax 1) a few simple functions

Alert (), # warning dialog box

Confirm (), # confirmation dialog box

Prompt (), # Input dialog box, received as a string

Config.log () # console output

Config.dir () #

document.write () #

typeof (variable) # type query

Syntax rules: JavaScript for line, indentation, space insensitive, end of statement with a semicolon, single-line comment//Multiline comment/*/

2) Direct volume, variable

(1) Direct Volume: Number 99 and string "99"

(2) Definition, assignment, naming specification of variables

var A;

A = 1;

· Naming conventions for variable names: only English letters, numbers, underscores, dollar sign $, and cannot start with a number, and cannot be a JavaScript reserved word. and case sensitive.

　　　　　　　　　　　　Camel 标记法

The first letter is lowercase, and the next letter begins with an uppercase character.  For example:var mytestvalue = 0, Mysecondvalue = "Hi" = 0, Mysecondvalue = "Hi" = 0, Smysecondvalue = "HI";

variable name writing type

3) Data type base data type:

String:

Number:

Number.max_value,number.min_value.

Nan is not equal to Nan

IsNaN (' Test ') #true

Infinity

Boolean:

Null:

Undefined:

Reference data type:

Array: Arrays

String:

Date:

Object:

4) Data type conversion

　　　　　　　　

• • • Number + String : Number converted to string
    • Number + Boolean: True converts to 1,false to 0
    • String + Boolean value : Boolean converted to string true or False
    • Convert to String: toString ()
    • Convert to Number: parseint ()
    • Convert to Floating point: parsefloat ()
    • Coercion Type conversions: String (), Boolean (), Number ()

5) Process Control # if () {}else{} # if () {}else if () {}else{} # && | | # while () {} # Do{}while () # for (Var i=0;i<10;i++) {},

# switch (condition) {//Note case penetrating problem

Case 1:

Execute the statement;

Break

Case 2:

Execute the statement;

Break

。。。。。。。。

Default

Execute the statement;

}

　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　

Second, Dom three, BOM

Python full stack development day44-js, DOM, BOM