emarketing concepts

1.URLThe URL that the user enters in the address bar--the Uniform Resource Locator. The URL information is sent to the server via an HTTP request, and the server returns the corresponding page file code to the browser based on the URL information.URL format: protocol name://host name. Domain name/directory path/file name2. Domain Name: Send the domain name to the DNS server to resolve the IP address corresponding to the domain name. Sends the domain name information to the Web server, w

effect is poor Core animation requires professional production, modified to be more troublesome CPU resources are relatively large, the page contains Flash animation when the page response is slow Apple's latest support, resulting in a drop in usage (2) HTML5 advantages recommended by the web, there is a unified network standard cross-platform, multi-device support seo friendly, use search engine crawl and search easy game development better interactivity audio and video

-128~127Short 2int 4Long 8 add L when writingFloating point type:Float 4 Add f when writingDouble 8 the default decimal typeCharacter type:Char 2 0~65535 can store Chinese charactersBoolean type:Boolean true False 2 Reference data typesData conversion: 1 implicit conversion (byte,short,char->int->long->float->double)2 cast Target data type variable name = (target data type) (result of operation);(int n = (int) (3.6));Nine, identifiersDefinition: A name used for a package, class, method, variabl

(1) WebSocket Protocol and HTTP protocolwebsocket 协议，双工通道 socket连接不断开http 协议 ，只能请求响应 (用户主动获取) socket连接断开都是基于socket ---- 客户端都是浏览器(2) polling 一般用户量少的 都是用 websocket来做即时通讯轮询 --- 一直发请求，定死的，2秒钟取一次长轮询 --- 请求之后，没有新消息，夯住，30秒之内没有新消息，断开 重新请求，如果有新消息，立刻返回消息(3) WS Protocol Small case创建 socket 服务端 import socket sock = socket.socket(socket.AF_INET,socket.SOCK_STREAM) sock.setsockopt(socket.SOL_SOCKET,socket.SO_REUSEADDR,1) sock.bind(('127.0.0.1',8002))

data is not valid, the algorithm can also make the relevant processing, rather than produce abnormal or strange and strange results.(4) High time efficiency and low storage capacityThe method of measuring the efficiency of the algorithm:(1) Afterwards statistical method: (unscientific, inaccurate)This method is mainly through the design of good test procedures and data, the use of computer timers on the programming of different algorithms to compare the running time, so as to determine the effi

, 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

public.installing third-party modulesIn Python, the installation of a third-party module is done through the Setuptools tool.If you are using Mac or Linux, install Setuptools itself this step can be skipped.If you are using Windows, please download ez_setup.pyfrom this address first:Https://pypi.python.org/pypi/setuptools#windowsinstallation method See the connection belowHttp://www.liaoxuefeng.com/wiki/001374738125095c955c1e6d8bb493182103fac9270762a000/ 0013868200214529634268c5b3b45b3a3ba1cd81

What is a data structure: Statistics + relationshipsRelationships can be divided into: sets, linear structures, tree structures, graph structures or network structures.Storage structure: Sequential storage, chained storage, index storage, hash storage.Data type: Atomic type, struct type1. Time complexity of the algorithm2. Spatial complexity of the algorithm2.1 Space occupied by the algorithm itself2.2 Space occupied by the algorithm at run time2.3 Temporary space occupied by the algorithm at ru

turn.Therefore, this processing method can guarantee the correctness of the program, there is no sale of the "0" ticket, "1" ticket. But at the same time, only one thread can get a lock. Execution speed is relatively slow.Using the Synchronized keyword is just one way to handle multithreading, and Java's JDK also provides concurrency control methods such as re-entry lock, read-write lock, condition object, semaphore semaphore, threadlocal thread local variable, and so on. Subsequent articles wi

erasing the drawing with the first drawing Destionation-atop: The drawing is drawn in the shape below the first drawing, two non-overlapping places, the first drawing will be completely transparent Lighter: After drawing the drawing with the value of the overlapping part of the drawing first, make the part brighter Copy: Draws a graphic that completely replaces the first drawing that overlaps with it XOR: Performs an "XOR" operation on the portion of the drawing that ove

statement does this: if the user does not enter any numeric values, then print will not be output and will be avoided by the addition of 0.8. Feature 8: Creation and invocation of functionsfunction creation Syntax:def functionname (arguments):SuiteHere, argument is optional, and if you have multiple arguments, you must separate them with commas. Each Python function has a return value of none by default, unless we use the syntax return value to return from the function, at which point value is

the target object.When was the proxy object created?Spring creates a proxy object when the agent's bean is actually applied.When is the object being proxied created?If you use Appplicationcontext,appplicationcontext to load all beans from beanfactory, Spring creates the Proxied object.8. Spring supports only method-level connection points.There are several models of connection points in AOP, such as field and constructor access points.However, spring only supports method connection points, so y

modifying the value of arguments changes the value of the named parameter. function Doadd (num1,num2) {arguments[1]=10;alert (ARGUMENTS[0]+NUM2);}Doadd (0,20);ECMAScript all parameters are passed values, it is not possible to pass arguments by referenceThree. ECMAScript function is not overloadedOverloading refers to defining two functions with the same name, as long as the two defined signatures (the type and number of accepted parameters) are different.ECMAScript two functions with the same

following procedure is done in the example above: first create a new string that can hold 10 characters, then populate the string with "Java" and "script", and the final step is to destroy the original string "Java" and the string "Script", because these two strings are useless.② converted to a string:toString (): except for null and undefined, other numeric types have this method, and in most cases the method does not have to pass arguments. However, when you call the ToString () method of a n

1. About programming habits. When viewing the source code of the Web page (recommended Firefox configuration Firebug), good programming habits allow us to have a better understanding of the structure of the code, when reading someone else's code or debug to find the problem.DOCTYPE HTML>HTML>//shengHead>MetaCharSet= "UTF-8">title>helloworld!title>Script>...Script>...Head>Body>...Body>HTML>2.basic expressions#contentEditable: Global properties that allow users to edit content inside an element#sp

Polymorphism refers to the same operation acting on a class of objects, which can have different interpretations and produce different execution results.Three necessary conditions for polymorphic existence Inheritance and implementation relationships need to exist The same method calls and performs different operations, running different code. A reference variable at run time for a parent class or interface can reference an object of its child class. The role of polymorphismPolymor

Package-based architectureTo ensure the flexibility and scalability of the system, VULCANJS uses a package-based architecture design, each of which is a package that can be easily added and removedExtend, not modifyVulcan's design philosophy is to extend the system rather than edit and modify the core base codeRegistration ExecutionMany Vulcan objects follow the pattern of registration execution All entries are preferred to be registered in a centrally-formatted array Entries are exec

works, know how to judge it in a function, and recognize why it is useful.6. NewRecognize how it relates to object-oriented programming. Learn what happens to functions that are called through new. Understand how the inherited objects from the function prototype property are generated by using new.7. Apply, call, bindLearn how these functions work and learn how to use them. Learn what they do to this.8. Prototypes and Inheritance (Prototypes Inheritance)Understand that inheritance in JavaScrip

Closures have always been a mysterious and profound feeling to programmers, including JavaScript programmers, and in fact, the concept of closures is not an incomprehensible knowledge in functional programming languages. If the basic concepts such as the scope, the function for the independent object understood better, the understanding closure concept and in the actual programming practice application is quite ripe for the feeling. In the case of DO

other content.Let's build a urllib2_test11.py to test the application of info: Copy Code code as follows: From URLLIB2 import Request, Urlopen, Urlerror, Httperror Old_url = ' http://www.baidu.com ' req = Request (old_url) Response = Urlopen (req) print ' Info (): ' Print Response.info () The results of the run are as follows, and you can see the information about the page: Here are two important concepts in URL