JavaScript (eight)--review One (important content is basically included)

first, The common dialog box

1. Alert (""): Warning dialog box, function is to pop up a warning dialog box

2. Confirm (""): OK Dialog box, pop up a dialog with OK and cancel Button--ok return true, Cancel return false

3. primpt ("text to display"): A dialog box that allows the user to enter content

Ii. Basic Grammar (similar to C #)

1. variables

are generic type var, can store other types of values, can be used directly, not defined. But it's customary to define.

Defining variables: var a; //all variable definitions are defined with var, var is a generic mutable type.

var s = "3.14";

2. Type conversion

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

Other types are converted to integers:parseint ();

Other types convert to Decimals:parsefloat ();

3. Operators

math operator : +-*/% + +-;

relational operators : = =! = >= <= > <;

logical operator :&& | | ！ ；

Other operators : + = = *=/=%=? ：；

4. statements

It is generally divided into sequential, branching, and cyclic statements.

(1) spoke statement: if{}else{} if{}else{}

(2) loop for statement :

5. Arrays

definition of the array: new array (); Its length is dynamically variable and can be placed in any type of Element.

Assignment of array elements: a[0]=123;  a[1]= "hello"; the index in the//element starts at 0.

The value of the array: a[i];

Array properties:a.length; the number of elements in the//array, Length. No Count ()

Methods: A.sort (); //array sorting, Sorted by the first character of each Element.

A.reverse (); //flip an Array.

6. Functions

four elements of a function: name, input, return value, processing.

Define Functions: function Add (formal parameter) {function body} //function named add, input as parameter, return value can be var type, or return Value.

anonymous function: function () {body}

The function must be called to Execute. Call to function: add (argument)

third, Windows objects

(a) part

window.open ("open address", "open Position")

Window.opener: Open the previous Page object for this page

Window.close (): Close the current page

Window.navigate ("url") jump to the target page (hyperlink), in Google Chrome under the bug; (not used)

Window.moveto (x, Y) Moves the page to a location that is determined by X and y; (not commonly used)

Window.resizeto (wide, High) Adjusts the width and height of the page (not commonly Used)

Window.scrollto (x, Y) Scrolls the page to where Y represents portrait scrolling; (not used)

(ii) Window.history Object

window.history.back (); page Back;--main remember

Window.history.forward (); Page forward;

Window.history.go (n); n If a positive number represents the forward n pages, N is a negative number that represents back n pages, which is commonly used.

(iii) Window.location Object

Location Bar

window.location.href= "http://www.baidu.com"; Change page address, will jump page (hyperlink)--mainly remember

Iv. Windows Object--window.document Objects

It can extract elements from HTML into js, and then perform various operations on it.

It is the core of JS in the core

(i) Take the element

★docunment.getelementbyid ("id"); Search by id, up to one;

★docunment.getelementsbyclassname ("name") According to classname, find out the array;

★docunment.getelementsbyname ("name"); Search by name, find the array;

★docunment.getelementsbytagname ("name"); based on the name of the tag, find out the array;

Note: It is best to use the ID and classname

(ii) Operation Contents

1. Common Elements

value : Alert (a.innerhtml)-- All content within the element, including element tags, is taken out

Alert (a.innertext)-- takes only the text inside, ignoring all the compiled elements

Assignment : a.innerhtml = "<font color=red >hello World </font>"-- If content has elements, it is implemented after compilation

A.innertext--will present the things that are Assigned.

2. Change single element

value : var t = document.f1.t1--form Form ID is F1 with ID t1 input;

var t = document.getElementById ("id")--obtained directly with ID.

Alert (t.value)-- Gets the value in input;

Assignment : t.value= "content change";

Note: all form element values are assigned with value

(ii) Operation Properties

1. Adding and modifying attributes

Object. setAttribute ("property name", "property value")--if No This property is added, the value of this property will be modified instead

2. Get properties:

Object. getattribute ("attribute Name")--gets The value of the property;

3. Delete Attributes:

Object. removeattribute ("property name")--removes a Property.

(c) Operation Style

1. Add and Modify Styles

Object. style. Style name = value
2. Get style

var ... = objects. Style. style name

(iv) operation of relevant elements--writing general purpose special effects

var a = document.getElementById ("id"); find a;

▲var B = a.nextsibling-- Find the next sibling element of a, Note that it contains spaces;

▲var B = A.previoussibling--find the previous sibling element of a, Note that it contains spaces;

▲var B = a.parentnode-- Find the Upper-level parent element of a;

▲var B = A.childnodes--is an array, looking for the next level of a sub-element;

▲var B = A.firstchild--first child element, lastchild last,childnodes[n] Find the number;

▲alert (nodes[i] instanceof Text);--judgment is not text, is return true, not return flase, use if to determine if its value is false, you can remove the Space.

V. Events

1. Onclick: Mouse click Trigger

Ondblclick: Double-click Trigger

2, Onmouseover: mouse movement above the trigger

Onmouseout: triggers when the mouse leaves

3, Onblur: Trigger when losing focus

Onfocus: get focus is trigger

4, onkeyup: Trigger when the button is lifted up

Complement: 1, Get the current height, width of an element ...--offsetheight, offsetwidth, offset what ...

2. Browser size Change event triggered: window.onresize

Note: some of the unused content can be seen in the previously published JavaScript essays

JavaScript (eight)--review One (important content is basically included)