javascript oops concepts

been defined, that is, the TypeOf action is used to detect its type, but the typeof operator is executed for variables that have not yet been defined and uninitialized, and they return the same results, all of which are undefined valuesNull typeA null type, and only one value, or null. A null value is logically represented as an empty object pointer. So when it detects the type, it returns "Object". var car=null; Alert (typeof car);If you define a variable that will be used to store the o

Closures have always given a mysterious, advanced sense to programmers, including JavaScript programmers, and in fact, the concept of closures is not a hard-to-understand knowledge in functional programming languages. If you understand the basic concepts of scope and function as independent objects, it is quite a good idea to understand the concept of closure and apply it in practical programming practice.I

= age;} Static method. User.clone = function (user) {return new user () {user.getname,user.getage}}6. Static VariablesFor static methods, it is natural to think of static variables, and how to represent static variables in JavaScript. is divided into two situations1) private static variablesHere is involved in the knowledge of closures, do not understand the self-brain repair. Directly on the code:private static variable (function () {

) Each row defines a variable (2) Single row to define multiple variables, separated by commas2 Call variable-use the data content of the variableDefine variables first, then call variables [normal]When the browser loads the execution of the JavaScript code-from top to bottom, when a variable is called, the variable already exists? Call the variable first, then define the variable---"Undefined"Console.log (TEST2); ==> var test2; --Define the variable

Before talking about the above concepts, we should first talk about the implicit parameter of the function in Javascript: arguments Arguments This object represents the function being executed and the parameters of the function that calls it. [Function.] arguments [n] Parameter function: option. Name of the Function object currently being executed. N: option. The index of the parameter value starting from 0

V8 JavaScript engine has very few documents. I only found two documents: 1. Official embedder's Guide: http://code.google.com/apis/v8/embed.htmlHttp://blog.csdn.net/ffr225/archive/2010/08/13/5809766.aspx. 2. Using V8-Google's Chrome Javascript Virtual Machine http://goo.gl/DRsoHttp://goo.gl/RyxE and http://goo.gl/QiYVBasic Concepts L handle: handle. All V8 obj

In the last share of javascript--function parameters and closures--in detail, the closure of the explanation is not deep enough. After a period of learning, I have a new understanding of the concept of closures. So the process of learning to organize into articles, one is to deepen their understanding of closure, the second is to provide readers with the way to learn, to avoid detours.In the javascript--fun

Fully understand the Javascript caller, callee, call, and apply Concepts [reprinted] Before talking about the above concepts, we should first talk about the implicit parameter of the function in javascript: arguments Arguments This object represents the function being executed and the parameters of the f

prototypes. If you understand the above concept, this picture is not difficult to read.From there, you can see an interesting place. Function.prototype.__proto__Point Object.prototype to, this explanation Function.prototype is an Object instance, then should be first Object there again Function . But Object.prototype.constructor.__proto__ it's pointing again Function.prototype . In this way, there is no Function , Object nor can I create an instance. This produces a kind of "f

, except for the left 1 of the decimal point), exponent 4 (binary shift code 00000000010), sign bit 0 = = Computer Storage: 0 00000000100 10011001100110011 ... 11001 = = Because the mantissa is up to 52 bits, the actual stored value is 0.00011001100110011001100110011001100110011001100110011001 and the decimal 0.2 = = Binary 0.0011001100110011 ... (Cycle 0011) = = Mantissa is 1.1001100110011001100 ... 1100 (total 52 digits, except for the left 1 of the decimal point), exponent 3 (binary shif

to say that the scope of a variable defined inside a function is inside a function? Now why is it accessible outside of the function? The first example differs from this example in that the variable defined inside the function in the first example uses the var operator, but there is no var operator, what does it mean? In other words, a variable defined inside a function, if not using the var operator, is a global variable. The above three examples are in normal mode, but ECMAScript 5 in the str

. 　　　　function isNaN () to determine whether the parameter is "not a numeric value"; IsNaN (NaN) //true IsNaN (//false converted to 10　　　　IsNaN ("Blue")//true numeric conversions varnum = Parentint ("1234blue");//1234varnum = Parentint ("")//NaNvarnum = Parentint ("0xa")//Tenvarnum = Parentinr (22.5)// Avarnum = Parentint ("070")// Aboutvarnum = Parentint ("70")// -parsing octal ECMAScript3There's a disagreement with ECMAScript 5 .varnum = Parentint ("070")//3 ECMAScriptvarnum = Pa

and Call methods: Bind functions to other objects to execute.Apply: The parameter will be passed in as an array;Call: Parameters are separated by commas and passed in as a list.1 functionClassA ()2 {3 This. Name= ' ClassA ';4 This. methoda=function(msg) {return This. name+ ': ' +msg};5 }6 functionClassB ()7 {8 This. Name= ' ClassB ';9 This. methodb=function(msg) {return This. name+ ': ' +msg};Ten } One varObja=NewClassA (); A

situation can be simulated and programmed for "object".(2) An "object" is a container that encapsulates the property and method.The so-called "attribute" is the state of the object; the so-called "method" is the object's behavior (accomplishing a certain task). For example, we can abstract an animal into a animal object, and the "attribute" record is specifically the animal, "method" means an animal's behavior (running, hunting, resting, etc.).Second, a typical object-oriented programming langu

The client JavaScript program uses an asynchronous event-driven programming model. Several concepts of related events: 　　Event Type: The string used to describe what type of event occurred; 　　Event Target: the object in which the event occurred; 　　event Handler Handler: a function that handles or responds to an event; 　　Event object: An object that is related to a specific event and that contains detai

(basic data type) Undefined Null Boolean Number String 2, 1 types of complex data Object //本质上是由一组无序名值对组成的 3. Typefo operator(1), a type of operator used to detect variable data types //对一个值使用typeof操作符可能返回以下某个字符串 "undefined"//如果这个值未定义 "boolean"//如果这个值是布尔值 "string"//如果这个值是字符串 "number"//如果这个值是数值 "object"//如果这个值是对象或者null "function"//如果这个值是函数 var int1; var int2=t

Javascript|js|jscript|vbscript| concept Many people are confused by these nouns, here to make a summary, thoroughly clarify these concepts. Javascript JavaScript was first developed by Netscape, the original name LiveScript, which was designed in part by Java, and the Java language was so hot t

, to determine1 functionhandlemessage (Message,handle)2 {3 returnhandle (message);4 }5 6 //determine if handle is a function before calling7 functionhandlemessage (Message,handle)8 {9 if(typeofHandle = = "function")Ten{returnhandle (message);} One Else A{Throw NewError ("The 2nd argument should be a function");} -}When the typeof phase is simultaneous:1 varobj = {};2 varArray = ["One", "one", "three"];3 4PrinttypeofMB ();//Object5PrinttypeofArray);//Object6 7Print (objinstanceofArray

English uppercase and lowercase letters and Arabic numerals are unsafe characters and need to be URL encoded. Here is my reference to the Tomcat source package under the Org.apache.catalina.util.URLEncoder, the String URL encoding tool class:Package Org.apache.catalina.util;import Java.io.bytearrayoutputstream;import Java.io.outputstreamwriter;import Java.util.bitset;public class urlencoder{protected static final char[] hexadecimal = {' 0 ', ' 1 ', ' 2 ', ' 3 ', ' 4 ', ' 5 ', ' 6 ', ' 7 ', '

The basic concepts of JavaScript forum post is a summary of some advanced js skills. 1. About this object The Code is as follows: View plaincopy to clipboardprint?Var obj1 = new Object ();Var obj2 = new Object ();// Add the property p to both objects, which is equal to 1 and 2, respectively.Obj1.p = 1;Obj2.p = 2;// Add a method to obj1 to display the value of p.Obj1.getP = function (){Alert (this. p); //