9.12/CSS3 expansion, JS Basic syntax, program basics, data types, operator representations, statement Knowledge points

CSS3 Expansion :

<display:none> Hide an element <visibility:hidden> also hide an element

<display:block> Display <visibility:visible> Display

The difference between <display> and <visibility> is that:<display> does not occupy position <visibility> hidden post position

When the two <div> overlap, internal <div> is displayed when the internal <div> is larger than the external one.

<overflow:hidden> out of section hidden

<scroll> out-of-section scroll bar display

Transparent: opacity:0.5; -moz-opacity:0.5; Filter:alpha (opacity=50) Three of these are used together in order to be compatible with a variety of browsers

Fillet: border-radius:5px (can adjust pixels to change the fillet size)

Transparent: box-shadow:0 0 5px 5px white;

(distance from X-axis) (distance from Y-axis) (how far the shadow is from the Div) (thickness of Shadow) Color

JS Basic grammar, program Basic knowledge, data type, operator expression, statement : JS code use principle: try to lean down

Basic knowledge of the Program:

① all characters are half-width english;

② in most cases, a semicolon is added to the end of each statement;

③ each piece of code at the end of the add line;

④ write the program must be back and forth (example: when the front of the parentheses, the back must also have parentheses to End)

Basic Syntax:

⒈ comment syntax: single-line comment://multiline comment:/* */embed format <script type= "text.javascript" > try to lean down

⒉ output syntax: ①alert (informational hint, popup): pop-up window.

②confirm (pop-up info): pops up a dialog box that interacts with the user

③prompt (pop-up info): pops up a dialog box for the user to enter

Data type:

⒈ variables: data is stored in the program, and the stored name is called a variable. In general, variables are used to store Data. (generic type var, can store other types of values Casually)

① strongly typed languages: classified archives, stored in corresponding data type variables

② weakly typed languages: regardless of what type of data is entered, the storage is the same, and in this type language, the type is automatically Converted.

⒉ Storage Type:

① number class: ⑴ shaping (integer): int⑵ single precision fractional: Float⑶ double decimal: Double⑷ decimal: Decimal

② Currency type: Money

③ Character: Char

④ string: String

⑤ Boolean (can only store two states, logic is true or false): 1, true: true 2, false: false

⑥ Date Time type: datetime

⒊ variable definition:

var a = 10;

var B = 5;

var C = a+b;

Alert (c) alert: Output

If you define a decimal or integer variable, the value after the equal sign is written directly

If you define a variable of a string, the string after the equal sign must be enclosed in double quotation marks (single quotation marks)

If you define a boolean, write directly after the equals sign (example: var sex (gender) = true;)

⒋ Conversion Mode:

To Integer: parseint (conversion content); Parse

Operator Expression:

⒈ Mathematical operators: +-*/(in strongly typed languages, integers/integers must be equal to integers)%

⒉ logical operator: &&: and (multiple conditions must be set up Simultaneously) | |: or (to satisfy one of these conditions can be established)!: non-

⒊ string concatenation: also with + (+ on both sides as long as there is one side of the string is Stitching)

⒋ ternary operator: var a = 8;

var B = 5;

var c = a==b? " A equals B ":" A is not equal to B "

Conditions (show content When set Up) (show content when not established)

The front can also write true or False

⒌ comparison operator: Determines whether equals: = = judgment is not equal to:! = to determine whether the value is greater than:> is less than:<

Judge whether Daewoo Equals: >= judgment is less than equals: <=

statement: if switch

⒈ sequential Statements: execute from top to bottom, plus semicolons at the End.

⒉ Branch Statement: Let the program execute different code depending on the Condition.

example: var a = 10;

var B = 5;

Conditions

Example: if (a==b)

{

Alert (the code executed when the condition is met) such as ("123")

}

else if (a>b) means so if

{

Alert (code executed when the else if condition is met) such as ("789")

}

Else: Then

{

Alert (code executed when the condition is not met) such as ("456")

}

Example: If nesting

Condition: A = 5;

If (a>2)

{

If (a>3)

{

Alert ("123")

}

Else

{

Alert ("456")

}

}

Example: switch

condition: var a = 3

Switch (a)

{

Case 1:

Alert ("123");

Break Break (jump, which is the direct output after satisfying the condition, does not execute the following Code)

Case 2:

Alert ("456");

Break

Case 3:

Alert ("789");

Break

Default:default (executes This statement when all case is not true on the current Face)

Alert ("the input is no longer in Range")

}

9.12/CSS3 expansion, JS Basic syntax, program basics, data types, operator representations, statement Knowledge points