JavaScript Global objects

Global Object

The most specific object in the global object ECMAScript, because from that point of view, the object is not present.

IsNaN (), Isfinite (), parseint (), and parsefloat () are all actually methods of the global object. In addition to this, global also contains other methods.

1.URI Encoding method

The encodeURI () and encodeURIComponent () methods can encode URLs for sending to a browser.

The encodeURI () method allows you to encode a URL with a hollow lattice character

The encodeURIComponent () method can replace non-alphanumeric characters in a URL with character encoding

The decodeURI () method converts a space character encoding in a URL to a character that corresponds to a encodeuri ()

The decodeURIComponent () method converts all non-alphanumeric character encodings in a URL to characters that correspond to encodeURIComponent ()

The 2.eval () method is hailed as the most powerful method

The eval () method parses and executes the incoming string code with the ECMAScript parser. Accept only one parameter

Eval () execution method takes too long to run

When the parser discovers that the eval () method is called in the code, it parses the passed-in parameter as the actual ECMAScript statement, and then inserts the result of the execution into the original location. Code executed through the eval () method is considered part of the execution environment that contains the call, so the executed code has the same scope chain as the execution environment.

Properties of 3.Global Objects

Property	Description
Undefined	Special value undefined
NaN	Special Value Nan
Infinity	Special Value Infinity
Object	Constructor Object
Array	Constructor array
Function	constructor function
Boolean	Constructor Boolean
String	Constructor string
Number	Constructor number
Date	Constructor date
Regexp	Constructor RegExp
Error	Constructor error
Evalerror	Constructor Evalerror
Rangeerror	Constructor Rangeerror
Referenceerror	Constructor Referenceerror
SyntaxError	Constructor SyntaxError
TypeError	Constructor TypeError
Urierror	Constructor Urierror

//1.URI Encoding MethodvarURI = "Http://www.wrox.com/illegal Value.htm#start"; Console.log (encodeURI (URI));//Http://www.wrox.com/illegal%20value.htm#startConsole.log (encodeURIComponent (URI));//Http%3a%2f%2fwww.wrox.com%2fillegal%20value.htm%23startURI= "Http%3a%2f%2fwww.wrox.com%2fillegal%20value.htm%23start"; Console.log (decodeURI (URI)); Console.log (decodeURIComponent (URI ));//2.eval () methodConsole.time ("Eval1"); Eval ("Console.log (' Hi ')"); Console.timeend (' Eval1 '); Eval ("Console.log (decodeURI (URI))");//eval () ability to parse strings is very powerful, but also very dangerous. Therefore, you must be extremely cautious when using eval (), especially if you are using it to perform user input data. //4. Window Objectvarcolor = "Red";functionSaycolor () {console.log (window.color);} Window.saycolor ();//another way to get a global objectvarGlobal =function (){return  This;} (); Console.log (global)

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JavaScript Global objects