Array: an ordered collection of a series of elements
Properties:
Length: gets the number of elements in an array, the maximum index plus 1
Methods:
Sort (function): in the case of no sort number specified, arrange the elements in alphabetical order.
Reverse (): reverses the order of the elements in the array;
Concat (array1,arrayn): used to combine N Numbers into an array1 array;
Join (string): it is used to merge the elements in the array into strings. String is the separator.
Slice (start,stop): returns the elements from start to stop in the array. If the parameter is negative, it means the reciprocal start or stop elements.
ToString (): returns a string from all the elements of the array, separated by a comma;
String (string)
Properties:
Length: returns the length of a string, as in an array;
Methods:
Anchor (): this method creates the same markup as the anchor in HTML, format < A name = ""… > , to access string.anchor(chorName) by
ToUpperCase (): converts a string toUpperCase;
ToLowerCase (): converts a string toLowerCase;
IndexOf (a,b): find the position of character a in the string from the b character and return. If b is omitted, find from the 0 position by default.
ChartAt (I): returns the ith character in the string;
Substring (start,end): returns all characters in the string from start to end (but not the end itself);
Sub (): displays the specified string in subscript format;
Date: see details
Definition method:
A: var newdt=new Date() —> Create a time object and assign it to the current time; B: var newdt=new Date(milliseconds) —> Create a time object and set the value of the object in milliseconds with the delay time of GTM; C: var newdt=new Date(string) —> Assign a value to the newly created time object with a specific time string in a format that matches the Date object’s parse method. D: var newdt=new Date(year, month, day, hour, minute, second, millisecond) —> Assign values to objects in the order of year, month, day, hour, minute, second and millisecond.
Methods: to obtain the time; Set time; Format conversion
A: get the time
GetDate () — gets the current full time; GetYear ()— gets the current year GetMonths ()— gets the current month GetDay ()— gets the current date and day GetHours ()— gets the current hour GetMinutes ()— gets the current minute GetSeconds ()- gets the current seconds GetTime ()- gets the current time in seconds GetTimeZoneOffset - gets the current time zone offset information
B: set the time
Compare with the above, replace get with set, for example, getDate() —> SetDate ()
C: conversion method
ToGTMString () — a string converted to a Greenwich mean time expression; ToLocaleString ()— converts to a string expressed in local time ToString ()— converts time to a string Parse - read the time from a string that represents the time UTC- returns the difference in milliseconds between Greenwich mean time and the specified time
Math mathematics:
Properties: note that properties in mathematical objects refer to reads
E (=2.7182) — the base of the natural log. Natural log of 10(=2.30259) — natural log of -10; Natural log of LN2(=0.69315)— natural log of -2; (= 3.1415926) — PI PI SQRT1_2(=0.7071)— square root of 1/2 SQRT2(=1.4142)— square root of 2 Log of 2e (=1.44269)— log base 2 of E LOG10E(=0.43429)— log base 10 of E
Method: actually use of not much, depressed, all out
Sine of a — sine of a Cosine of a — find the cosine of a Tangent of a — tangent of a A sine of a — find the inverse sine of a Atan of a — find the arc cosine of a E to the a — to the exponent of a Log of a — let’s take the natural log of a Pow of a, I — a to the I power. Round (a)— round a SQRT of a — square root of a Abs of a — let’s take the absolute value of a Random ()— take a random number Max of a,b — take the larger number Min of a,b — take a smaller number
Note: the arguments to the function are floating-point, and the arguments to the trig function are radians, not degrees
Built-in functions for JavaScript
Escape () vs. unescape() : encodes and decodes strings
Eval (string): used to perform an operation or statement represented by a string For example, var a=0; Var str1 = a + = “a”; The eval (str1);
ParseInt () and parseFloat(): converts the value of a text box to an integer or floating point number
Note: instead of rounding Numbers, parseInt() cuts the ends
IsNaN (): the full E text is (is not a number), as the name implies to determine whether a string is a number, such as if(isNaN
Custom objects: there are two ways to initialize an object and to define an object with a constructor
A: initialize the object
For example: object ={attribute 1: value 1; Attribute 2: value 2; . Property n: value n}, note that each property \ value pair is separated by a semicolon;
B: the object that defines the constructor
Such as: Function name (attribute 1, attribute 2… Properties of N) {
This. attribute 1= attribute value 1; This. attribute 2= attribute value 2; This. Attribute n= attribute value n;
This. Method name 1= function name 1; This. Method name 2= function name 2; }
Note: the method name and the function name can be the same, but the function must be defined before the method calls the function, otherwise an error will occur
Creating a new instance of a custom function also USES the new statement.
Browser object
The window object: He belongs to the central level, the highest level of all objects, to put it bluntly, without him, you all have no fun;
Properties:
Closed — used to determine whether the window is closed; Er — store () method to open the parent window of the window; Defaultstatus — the information displayed in the status bar by default; Status — the information currently displayed in the status bar; The Document, the Location, the History - is very important, later said in detail, such as if you don’t want to, look here directly
Methods:
Alert (text)— a prompt message box pops up Confirm (text)— confirm message box, parameter is confirm message Prompt (text,default)- prompt(text,default)— the input dialog box pops up with prompt and default parameters
The document object: Include various features of the current page, such as title, URL, background, language, modification time, etc
Properties:
Title — document title LastModified - the last time a file was modified URL— the corresponding page address of the document Cookie— used to create and obtain Cookie information BgColor — the background color of the document FgColor - foreground of the document Location — save all the page address information of the document Alinkcolor - activates the color of the connection Linkcolor - the color of a link Vlinkcolor - the color of a browsed link
Methods:
Write (text)- writes text or tags to a document without breaking lines Writeln (text)- writes a text or label to a document, breaking the line at the last character ()— open a new document such as “address ”,” window name ”,” style” Close ()— close the current document
The Location object: Contains all page address information for the current document
Properties:
Protocol — communication protocol Host — the name of the WEB server where the page is located Port — the port number for server communication Pathname — the document’s path on the server Hash — anchor tag information for page jumps Searce — information submitted to a server for search Hostname — hostname and port number separated by colon Href — complete URL address
Methods:
Assign (URL)- navigate the page to another address Reload — refresh the page Replace (URL)- use the page with the specified URL to replace the current page
History: This object contains URL information that was previously accessed
Property: length, which returns the number of urls