What is a scripting language?
① scripting language between HTML and c,c++,java,c# programming languages
② scripting language has a similar place to programming language, and its functions are similar to programming languages, and there are variables. The biggest difference from programming languages is that the syntax and rules of a programming language are stricter and more complex.
③ scripting language is an explanatory language, such as Python, Vbscript,javascript, and so on, unlike c\c++, which can be compiled into binary code, in the form of executable files.
④ scripting language generally has a corresponding scripting engine to explain execution, JavaScript scripting engine is the browser
JavaScript is primarily intended for client-side programming (browsers) and server programming.
Event Source (Event object) event handler
mouse events;
keyboard events;
HTML events;
other events;
var a=10: Defines a variable with a value of 10 for the variable named A,a
Window.alert (a): Frame display, display () contents
document.write: Web page display (must be prefixed)
Break: Jump out of the loop
Continue: End this round cycle
Parse: Cast
parseint: Cast to an integer.
Parsefloat: Cast to floating-point
Meta charset= ' utf-8 ': Chinese
Script: Display
if (): judging (IF)
else: Otherwise (with if use)
Return: Value returned
For (i=1;i<50;i++): Loop 1
while (I<50): Loop 2
do{}while (i<50): Loop 3
Prompt: Input
getElementById: Sets the return value of an ID connection
Onclick:html Label Connection function
Disabled: text box cannot be clicked input
This: Object-oriented (me)
charCodeAt:
Floor: Fractional conversion of integers, such as 1.9=1;-1.9=-2;
SetTimeout: Timer Execution time
SetTimeout ("C ()", 5) executed every five milliseconds
Cleartimeout: Timing Stop
Function: Defining functions
Function usage: <script type= "Text/javascript" src= "JS (file path)" ></script>
function invocation: JS (JS is the function name), A=JS () (A is the variable name, JS is the function name);
charCodeAt: Returns the Unicode encoding of the character
Eval: Run string
Event.clienty: Display mouse coordinates
Event.clientx:
OffsetTop: Displays the distance from the top edge of the previous element to the top edge of the element
Offsetleft:
Offsetheight: Returns the height of the element
Offsetwidth: Returns the width of the element in pixels. This is a non-standard but well-supported property.
Date () returns the current date and time
GetDate () returns a day in one months from a Date object
GetDay () Returns a day of the week from a Date object
GetMonth () returns the month from the Date object
GetYear () returns the year from the Date object
GetHours () returns the number of hours from the Date object
Getminutes () returns minutes from a Date object
Getseconds () returns the number of seconds from the date object
Math.Abs (x) absolute value of the return number
Math.ceil (x) rounds a number
Math.floor (x) rounds a number down
Math.max (x, y) to find the larger number in X, y
Math.min (x, y) to find the smaller number in X, y
Math.Round (x) rounding X
Math.random () A number of 16-bit decimal digits greater than 0 and less than 1
IndexOf () returns the position of the first occurrence of a string value in the string
Split () splits a string into an array of strings
SUBSTR () extracts the specified number of characters starting from the start subscript
SUBSTRING () extracts a string that is mediated between two specified subscript sub-strings
CharAt () returns the character at the specified position
Length property, you can get the string
The loading of the onabort image is interrupted.
The onblur element loses focus.
The contents of the onchange domain are changed.
OnClick an event handle that is invoked when a user taps an object.
OnDblClick an event handle that is called when the user double-clicks an object.
OnError An error occurred while loading the document or image.
The onfocus element gets the focus.
OnKeyDown A keyboard key is pressed.
onkeypress A keyboard key is pressed and released.
OnKeyUp a keyboard key is released.
OnLoad a page or an image to finish loading.
OnMouseDown the mouse button is pressed.
OnMouseMove (*) mouse is moved.
onmouseout (*) The mouse moves away from an element.
onmouseover (*) moves the mouse over an element.
OnMouseUp mouse button is released.
The onreset reset button is clicked.
OnResize the window or frame is resized.
Onselect text is selected.
OnSubmit confirm button is clicked.
OnUnload user exits the page.
DOM element: (document.)
Createelemnet (sign) Create a node
AppendChild (node) append one node
InsertBefore (node, original node) Insert node before existing element
RemoveChild (node) Delete a node
ChildNodes NodeType Get child nodes
Childrenparentnode Get parent Node
GetAttribute (name) get
SetAttribute (name, value) settings
RemoveAttribute (name) Delete
By: space
<br/>: Line break
. appendchild Add
JS itself provides some of the classes that can be used directly are internal classes:
Mainly include:
JS Array
JS Boolean
JS Date
JS Math
JS number
JS String
The inner classes are divided into:
Static class
How to use static classes
When referencing its properties and methods: Static Class. Method (or property)
How to use dynamic classes
of the Dynamic class
var object instance name =new class ()
object instance name. Method (or familiarity)
String class: One of the dynamic classes.
One array:
1. Arrays can hold any type of data.
2. The array size does not have to be developed beforehand.
3. The array name can be interpreted as a reference to the first address of the array.
4. Array elements are numbered by default starting from 0.
New array: Creating an array
The JS array can grow dynamically
. Split: Splitting a string into a character array
Splits a string string. Split (split standard) to get an array of
Length: Returns the number of numbers in the array
Array name. Length---Usage
for (var key in arr) {Widow.alert (key+ "="-arr[key]);}
Create an array
var a=new Array (3)
A[0]=1;
a[1]=2;
a[2]=3;
Or: Var a=new Array ("1", "2", "3")
Creating a two-dimensional array
var a=new Array ();
for (Var i=0;i<10;i++) {
A[i]=new Array ();
for (Var j=0;j<20;j++) {a[i][j]=1;}
}
ScrollWidth is the width of the actual content of the object, without the width of the edge, which changes with the contents of the object (more content may change the actual width of the object)
ClientWidth is the width of the object visible, without edges such as the scroll bar, which changes with the window's display size.
The offsetwidth is the visible width of the object, and the edges such as the package scroll bar change with the window's display size.
ScrollHeight: Gets the scroll height of the object.
Offsetheight: Gets the object relative to the canvas or by the parent coordinate
ScrollLeft: Sets or gets the distance between the left edge of the object and the leftmost of the currently visible content in the window
Offsetleft: Gets the object relative to the layout or by the
ScrollTop: Sets or gets the distance between the top of the object and the top of the visible content in the window
The OffsetTop property specifies the top position of the calculated parent coordinate
The height of the parent coordinate specified by the OffsetParent property
The OffsetParent property specifies the parent coordinate of the computed left position
Event.clientx horizontal coordinates of relative documents
Event.clienty vertical coordinates of relative documents
Event.offsetx horizontal coordinates relative to the container
Event.offsety the vertical coordinate of the relative container
JS operator
①+ plus ②-minus ③* by ④/in addition to ⑤% to take the mold (take the remainder) ⑥++ self-added ⑦--self-reduction ⑧+= Zoga ⑨-= left minus ⑩/= left except ⑾%= left to take the mold
JS relational operators
①== equals ②> greater than ③< less than ④>= greater than or equal to ⑤<= less than equals ⑥!= not equal to
logical operators
①&& and ②| | or ③! Non -
Academy of Sciences
Mu class net
JavaScript (reprinted from the Academy of Science and Education Network)