What is &#x27;Contenteditable True Laravel 8&#x27;?In HTML5, we can set the contenteditable=&quot;true&quot; attribute to HTML tags to enable the user to edit the content in the tag on the browser side. Example. The Contenteditable attribute is compatible with all browsers (compatibility with versions before IE6 has not been tested), and in some cases, we can completely replace input or Textarea with a div to enable data collection. For example, when using ajax, we can get the content of a div when submitting a form. The DEMO code is as follows: {     &lt;style type=&quot;text/css&quot;&gt;       .demoEdit{     border:1px solid #dddddd;width:450px;min- height:20px;_height:20px;outline:0px;padding:2px;     } // outline:0px; The style solves the effect of the container getting the focus and displaying a dashed box in FF browsers.       .demoEdit p{     margin:0px;padding:0px;     }     &lt;/style&gt;       &lt;div contenteditable=&quot;true&quot; style=&quot;border:1px solid #dddddd;width:360px;min-height:20px;_height:20px;outline:0px;&quot;&gt;&lt;/div&gt;       &lt;div contenteditable=&quot;true&quot; class=&quot;demoEdit&quot;&gt;&lt;/div&gt;   } The cursor height will be as high as the container height or not show the cursor when the container gets the focus under FF browser, at this time if the container default adds a placeholder, such as &lt;br/&gt; or can solve this problem. The contentEditable property in Html can be used to turn on the editable state of certain elements. Perhaps you have never used the contentEditable property, or even heard of it, the role of contentEditable is quite amazing. You can make divs or entire web pages, as well as spans and other elements set to writable. The most common types of text we use are input and textarea. With the contentEditable property, you can enter content into divs, tables, p, spans, bodies, and many other elements. In particular, contentEditable is now supported in the html5 standard.If you need a VPS to run Laravel 8, you can choose LightNode. We provide stable and high-performance VPS hosting servers. Our VPS nodes locate in more than 20 locations in the world.Go to buy: <a href="https://www.lightnode.com" target="_blank">lightnode.com</a>

Library

Contenteditable True Laravel 8

Procedural programming and object-oriented programming embody two different ways of thinking for programmers, and this article focuses on the differences and connections between procedural programming and object-oriented programming. procedural programming is a process-centred way of thinking. It starts by analysing the steps needed to solve a problem, and then uses functions to implement these steps step by step, calling them in turn when they are used, a basic sequential way of thinking. The procedural development approach is a layer of abstraction from the underlying structure of the computer, which divides the program into two parts: the data and the operations that manipulate the data, with the core problem being the development and optimisation of data structures and algorithms. Common programming languages that support procedural development include C, COBOL and others. Object-oriented is a systematic way of thinking according to people&#x27;s understanding of the objective world, using the concept of building models based on objects (entities), simulating the objective world to analyse, design and implement software programming ideas, through the object-oriented concept to make computer software systems can correspond with the real world systems one by one. The object-oriented approach treats everything directly as an independent object, and what is considered in the process of dealing with a problem is no longer primarily how to describe it in terms of data structures, but directly how to reproduce the relationship between the various objects in the problem. The underlying implementation of the object-oriented approach also includes procedural thinking. Common programming languages that support object-orientation include C++, C#, Java and others. Specifically, object-oriented and procedural approaches differ in the following four ways. 1) Different starting points Object-oriented uses a conventional way of thinking to deal with problems in the objective world, emphasising the mapping of &quot;actions&quot; in the problem-solving domain directly onto the interfaces between objects. In contrast, process orientation emphasizes the abstraction and modularity of the process, and is process-centred construction or processing of objective world problems. 2) Different levels of logic Object-oriented use of computer logic to simulate the physical existence of the objective world, a collection of classes of objects as a unit to deal with the problem, as far as possible to bring the computer world to the objective world, in order to make the way to deal with the problem more clear and direct, object-oriented use of class hierarchy to reflect the inheritance and development between classes. The basic unit of procedural processing is the module that can clearly and accurately express the process, using the module hierarchy to outline the relationship and function between modules or modules, abstracting the objective world&#x27;s problems into processes that the computer can handle. 3) Different ways of data processing and control procedures Object-oriented data and the corresponding code encapsulated into a whole, in principle, other objects can not directly modify its data, that is, the object can only be modified by its own member functions to complete, control the program is through the &quot;event-driven&quot; to activate and run the program. The procedural approach is to process the data directly through the program, and to display the results of the process once it has been completed, in the control mode is to call or return to the program according to the design, and not to navigate freely. 4) Different ways of analysis and design and coding conversion Object-oriented throughout the software life cycle of analysis, design and coding, is a smooth process, from analysis to design to coding is the use of a consistent model representation, to achieve a seamless connection. In contrast, process orientation emphasises the transformation between analysis, design and coding according to rules throughout the software lifecycle, achieving a seamless connection. A comparison of the characteristics, advantages and disadvantages of object-oriented and procedural approaches is shown below. Object-oriented Features: abstraction, inheritance, encapsulation, polymorphism Advantages: easy to maintain, easy to reuse, easy to extend, low coupling Disadvantages: lower performance than procedural     Procedural Features: modularity of functionality, flow of code Pros: high performance, suitable for resource-constrained, real-time situations Disadvantages: not object-oriented easy to maintain, easy to reuse, easy to extend The object-oriented approach to programming has four basic characteristics. 1) Abstraction: This is the process of ignoring aspects of a subject that are not relevant to the current goal in order to pay fuller attention to aspects that are relevant to the current goal. Abstraction does not intend to understand the whole problem, but only to select a part of it, without using some of the details for the time being. Abstraction consists of two aspects, one being process abstraction and the other being data abstraction. Process abstraction means that any operation that explicitly defines a function can be viewed by the user as a single entity, although this operation may actually be performed by a series of lower-level operations. Data abstraction defines the data type and the operations imposed on an object of that type, and qualifies the value of the object to be modified and observed only through the use of those operations. 2) Inheritance: This is a hierarchical model for linking classes and allows and encourages the reuse of classes, it provides a way to explicitly express commonality. A new class of objects can be derived from an existing class, a process known as class inheritance. The new class inherits the characteristics of the original class, which is called the derived class (child class) of the original class, and the original class is called the base class (parent class) of the new class. A derived class can inherit methods and instance variables from its base class, and the class can modify or add new methods to make it more suitable for particular needs. This also reflects the relationship between the general and the particular in nature. Inheritance is a good solution to the problem of software reusability. 3) Encapsulation: This means that processes and data are enclosed and access to data is only possible through defined interfaces. Object-oriented computing begins with this basic concept that the real world can be portrayed as a series of fully autonomous, encapsulated objects that access other objects through a protected interface. Once the properties of an object have been defined, it is necessary to determine the visibility of these properties, i.e. which properties are visible to the external world and which properties are used to represent internal state. The interface to the object is defined at this stage. As a rule, direct access to the actual representation of an object should be prohibited and the object should be accessed through the operational interface, which is called information hiding. Encapsulation ensures that modules have a good degree of independence and makes it easier to maintain and modify the application. Modifications to the application are limited to the internals of the class, thus minimising the impact of changes to the application. 4) Polymorphism: This means that objects of different classes are allowed to respond to the same message. For example, the same copy-and-paste operation has different effects in a word processor and a drawing program. Polymorphism includes parametric polymorphism and inclusion polymorphism. Polymorphic languages have the advantage of flexibility, abstraction, shared behaviour and shared code, and are a good solution to the problem of homonymy of application functions.

Differences Between Procedural programming and object-oriented programming

1. BackgroundMutually exclusive access to shared resources has traditionally been a problem that many business systems need to solve. In distributed systems, distributed locks are often used as a general-purpose solution.2. From single-computer locking to distributed lockingIn a stand-alone environment, when a shared resource cannot provide mutually exclusive access itself, to prevent data corruption caused by simultaneous read/write access to the shared resource by multiple threads/multi-processes, a third party provides the capability of mutual exclusion, which is often the kernel or a library that provides the capability of mutual exclusion. . If we evolve to a distributed environment, we need a distributed service that provides the same function, different machines get a lock through the service, and the machine that gets the lock can access the shared resources in an exclusive way, so the service is collectively called distributed lock service, and the lock is also called distributed lock.To abstract the concept of distributed locks, first of all, a distributed lock needs to be a resource that provides concurrency control and outputs an exclusive state, that is.Lock = Resource + Concurrency Control + Ownership DisplayAs an example, take a common single lock.Spinlock = BOOL + CAS (optimistic lock)Mutex = BOOL + CAS + notification (pessimistic lock)Spinlock and Mutex are both a Bool resource, via the atomic CAS instruction: when it is now 0 set to 1, it holds the lock if it succeeds and not if it fails if it does not provide a display of ownership, e.g. AtomicInteger, it is also via the resource (Integer) + CAS, but it does not explicitly hint at ownership and therefore will not be, Of course, the &quot;ownership display&quot; can be seen more like a wrapper for some form of service provision.In a stand-alone environment, the kernel has a &quot;God&#x27;s perspective&quot; and can know the survival of the process and release the lock resources held by the process when it hangs, but in a distributed environment, this becomes a challenge, and to cope with various machine failures, downtime, etc., it is necessary to provide a new feature to the lock: availability.Any service that provides three characteristics can provide the ability of distributed locks. The resources can be files, KVs, etc. The availability of locks is ensured by creating atomic operations such as files and KVs, indicating ownership by the result of successful creation, and also by TTL or sessions.3. System Classification of Distributed LocksBased on the security of the lock resource itself, we classify distributed locks into two camps.- distributed systems based on asynchronous replication, such as MySQL, tair, Redis, etc.- distributed consistent systems based on the Paxos protocol, such as a zookeeper, etc., etc.In distributed systems based on asynchronous replication, there is a risk of data loss (lock loss), not safe enough, often through the mechanism of TTL to assume a fine-grained lock service, the system is simple to access, suitable for very time-sensitive services, expect to set a short validity period, perform short-term tasks, and the impact of lock loss on the business is relatively controllable.The distributed system based on the Paxos protocol, which guarantees multiple copies of data through consistency protocols and high data security, often undertakes coarse-grained lock services through the mechanism of leases (sessions), this system requires a certain threshold and is suitable for services that are sensitive to security, wish to hold locks for a long time and do not expect lock loss to occur.

Technical Practice of Distributed Locking in Storage Systems

Process: is a basic unit of concurrently executing programs that allocates and manages resources during execution, and is a dynamic concept that competes for the resources of a computer system.Thread: An execution unit of a process, a scheduling entity within the process section. A basic unit of independent operation that is smaller than a process. Threads are also known as lightweight processes.A program has at least one processor and a process has at least one thread.Differences between processes and threadsAddress space: Threads of the same process share the address space of this process, while processes are independent of each other.Resource ownership: Threads within the same process share the resources of this process such as memory, I/O, CPU, etc., but the resources between processes are independent.When a process crashes, it does not affect other processes in protected mode, but a thread crashes and the whole process dies. So multi-process is more robust than multi-thread.Process switching consumes more resources and is more efficient. So when it comes to frequent switching, it is better to use threads than processes. Similarly, if concurrent operations are required and some variables are shared, only threads can be used and not processes.Execution process: Each independent process has a program entry, a sequential execution sequence, and a program entry. However, threads cannot be executed independently and must be dependent on the application, which provides control over the execution of multiple threads.Threads are the basic unit of processor scheduling, but processes are not.Both can execute concurrently.Thread safety is a concept in computer program code when programming with multiple threads.In programs where multiple threads with shared data are executing in parallel, thread-safe code ensures that each thread can execute properly and correctly without surprises such as data contamination through synchronization mechanisms.Thread safety problems are mostly caused by global and static variables, and local variable escapes may also cause thread safety problems. If each thread has only read operations on global variables and static variables, but no write operations, the global variables are generally thread-safe; if multiple threads perform write operations at the same time, thread synchronization should be considered, otherwise, thread safety may be affected.

Difference Between Threads and Processes? What Is Thread Safety

BGP (Border Gateway Protocol) is a routing protocol used to connect independent systems on the Internet. It is an enhanced, refined, and scalable protocol developed by the Internet Engineering Task Force.BGP4 supports the CIDR addressing scheme, which increases the number of available IP addresses on the Internet.BGP was designed to replace the original Exterior Gateway Protocol, EGP. It is also considered to be a path vectoring protocol.BGP is mainly used for interconnection between Internet AS (Autonomous Systems). The most important function of BGP is to control the propagation of routes and to select the best route. After interconnection using the BGP protocol, all backbone routing devices of network operators will judge the best route to the IP segment of IDC rooms to ensure high-speed access for users of different network operators.The server room that uses the BGP solution to achieve dual-line interconnection or multi-line interconnection is called the BGP server room.Advantages of BGP server room1. The server only needs to set an IP address, and the best access route is determined by the backbone router on the network according to the number of route hops and other technical indicators, which will not take up any system resources of the server. The server&#x27;s uplink and downlink routing can choose the optimal path, so it can truly achieve high-speed single-IP high-speed access.2. because the BGP protocol itself has the characteristics of redundant backup and loop elimination, so when the IDC service provider has more than one BGP interconnection line that can achieve mutual backup of the route, the route will automatically switch to other lines when a line fails.3. the use of BGP protocol can also make the network has strong scalability can be interconnected with other operators IDC network, easy to achieve a single IP multi-line, to do all interconnected operators of the user access are very fast. This is a dual-IP dual-line that can not be compared.BGP server room line technologyBGP is a routing protocol between autonomous systems, and its main function is to exchange network reachability information with other BGP speakers. A BGP speaker is any device configured for BGP. BGP uses TCP as its transport protocol (port 179), which provides reliable data transfer.Two BGP routers form a transport protocol connection. These two routers are called neighbors or peers. Once the transport connection is formed, the two pairs of routers exchange messages to open and confirm the connection parameters. In this step, the routers exchange information such as BGP version number, AS number, duration, BGP identity, and other optional parameters. If any of the parameters do not agree between the peers, an error notification is sent and this peer connection is not established.If the peer routers all agree on these parameters, the entire BGP routing table is exchanged via the UPDATE message, which contains a list of reachable destinations through each system (i.e., Network Layer Reachability Information NLRI) and the path attributes for each route. The path attributes contain information such as the source of the route (ORIGIN) and the level of priority.The BGP table is valid for each peer during the BGP connection. If a routing message changes, neighboring routers use incremental updates (messages) to pass this information. BGP does not require that routing information be refreshed. If no route changes are generated, BGP peers only exchange keepalive messages, which are sent periodically to ensure that the connection is kept alive.BGP server room advantage analysisBGP room is the server renters through the technical means, the actual different operators can access a common IP, and different operators can achieve the fastest access speed between the relevant network technology.BGP server room to a certain extent to solve the problem of north-south interoperability of various users, improve the access speed of users, and the effect of single IP dual lines realized with the BGP protocol. The program is through the BGP protocol, directly one of the lines of IP mapping another line IP, when visitors browse your website, will automatically select the fastest line of access according to the actual situation so that users of various operators can achieve the best access speed.1. The rented server has only one IP, and the user&#x27;s access route is chosen by the router to access according to the visitor&#x27;s actual access speed by selecting the optimal access path. And does not take up any server resources. The server&#x27;s uplink and downlink are routers to choose the best route, so this can achieve the best access speed between operators to achieve the real BGP effect.2. Because the BGP protocol itself has the characteristics of redundant backup, eliminating loops, when you host or rent a server failure, you can achieve mutual backup. The company&#x27;s main business is to provide a wide range of products and services to its customers.3. The BGP server rental is also a good expansion and integration and can be realized and other operators interconnection, easy to achieve a single IP multi-line, so that all interconnected operators of the user access is very fast. This is a dual-IP dual-line server rental that can not be achieved.

What's LightNode's BGP Server Room?

Overview:1. Solid State Drive (SSD), the internal structure of the SSD is not as complex as the HHD, SSD is a hard disk with solid state electronic storage chips arrayed from the control unit and storage unit, the storage medium is divided into two types, one using flash memory (FLASH chips) as the storage medium, the other is the use of DRAM (DRAM chips) as the storage medium.Inside the SSD, the most core part is the controller, which is the heart of the entire SSD, including many architectures, such as read and write algorithms, interface definitions and so on. SSDs are identical to traditional hard drives in terms of interface specifications and definitions, functionality and usage, and are also identical to traditional hard drives in terms of product shape and size, with greatly improved I/O performance compared to traditional hard drives.The chips have a wide operating temperature range of commercial (0 ~ 70°C) and industrial (-40 ~ 85°C). Although the cost is higher, it is also gaining popularity in the DIY market.Because SSD technology is different from traditional hard drive technology, it has given rise to a number of emerging storage manufacturers. Manufacturers can build SSDs by simply purchasing NAND memory and pairing it with the appropriate controller chip.2. Mechanical Hard Disk (HHD): that is, the traditional ordinary hard disk, mainly composed of: disk, head, disk spindle and control motor, head controller, data converter, interface, cache and other parts.In the center of each HHD, there are a large number of high-speed rotating disks, all the disks in the HHDs are mounted on a rotating axis, each disk is parallel to each other, the disk is covered with a layer of small and thin magnetized metal particles, data in a form that can not be distinguished by the naked eye, many groups of tiny particles formed by the magnetization pattern records form the data, each group of data is also called bit, all The particles are arranged according to their own magnetism, which works similarly to the CD-ROMs we normally use. The advantage of a SSD is that it can store more things than a SSD at the same price.The surface of each disk has high-speed sweeping recording heads, the distance between the heads and the disk is smaller than the diameter of a hair, all the heads are linked to a head controller, and the head controller is responsible for the movement of each head, the heads can move along the radius direction of the disk, together with the high-speed rotation of the disk of several thousand revolutions per minute, the heads can be positioned at the specified location on the disk for data reading and writing operations.Information is passed through the magnetic surface very close to the magnetic head, by the electromagnetic flow to change the polarity way by the electromagnetic flow to write to the disk, the information can be read in the opposite way. As a precision device, dust is the big enemy of the hard disk, so the air entering the hard disk must be filtered.SSD advantages:1. Read and write speed: the use of flash memory as a storage medium, read speed is faster compared to mechanical hard drives. SSD do not use magnetic heads, and the seek time is almost 0. The sustained write speed is amazing, and most SSD manufacturers say they will claim that their own SSD sustained read and write speeds of more than 550MB/s! SSDs are definitely not only fast in terms of sustained read and write, but also in terms of random read and write speed, which is the ultimate mystery of SSDs and is most directly reflected in the vast majority of daily operations. Related to this is the extremely low access time, the most common 7200 rpm mechanical hard drive seek time is generally 12-14 milliseconds, while SSD can easily reach 0.1 milliseconds or even lower.2. Shock and drop resistance: traditional hard drives are disk-based, with data stored in the disk sectors. While SSDs are made using flash memory particles (i.e., mp3, U disk and other storage media), so SSD hard drives do not have any mechanical parts inside, in the event of collisions and shocks to minimize the possibility of data loss.3. low power consumption: the power consumption of SSD is lower than that of traditional hard drives.4. no noise: SSD do not have mechanical motors and fans, working at a noise level of 0 decibels. There are no mechanical moving parts inside, no mechanical failure, and no fear of collision, shock, vibration. Because SSDs use flash memory chips with no mechanical parts, they have the characteristics of low heat generation and fast heat dissipation.5. Large operating temperature range: Typical hard disk drives can only operate in the range of 5 ~ 55 degrees Celsius. Most SSDs can operate at -10 ~ 70 degrees Celsius. The interface specification and definition, function and usage of SSD are the same as those of ordinary hard drives, and they are also consistent with ordinary hard drives in terms of product shape and size. The chips have a wide operating temperature range (-40 ~ 85 degrees Celsius).6. Lightweight: SSD are very light in weight, compared with the conventional 1.8-inch hard drive, 20 ~ 30 grams lighter, now M.2 and other SSD can do and memory size, compact and lightweight, very convenient to carry every day.SSD compared to HHD:1. Access speedSSD have a great advantage in transfer speed, up to 500M / s, where the read speed reaches 400-600M per second, the write speed can also be as high as 200M per second. For 1G files in just a few seconds, while the traditional IDE hard drive read speed limit is unable to exceed 200M per second, write speed is also difficult to break 100M per second, usually basic in a few dozen M per second.2. Economic priceSolid-state more disk in speed and security has a great advantage, because it is the latest technology so in terms of price relative to traditional hard disk is much higher, SSD are now generally 2-3 times the price of traditional hard disk.3. Data securityWe all know that the traditional hard disk is through the head to read the disk to complete the data read and write, especially in the high-speed rotation process of the disk and head collision is more likely to cause data damage, and solid-state hard disk no disk, so as long as its chip is not extruded by the shape of the deformation, the data can be safely preserved, so the difference between solid-state hard disk and ordinary hard disk in terms of data security is great.Generally speaking, HHD damage data can be recovered, but this is not 100%, individual cases can also cause unrecoverable. The SSD data is basically very difficult to recover, and this is the biggest shortcoming of the SSD. So it is recommended that if you have important information or exist in the mechanical hard drive is safer, or use a different SSD for backup. At least for now, it is unknown later.4. Seismic capacityHHD because of the use of high-speed rotating platters and heads back and forth seeking the principle of reading and writing data, so there can not be high-intensity vibration, otherwise the heads and high-speed rotating platters in contact with the platters will cause scratches and damage to the platters, resulting in the scrapping of the hard disk, so the use of HHD must avoid the occurrence of vibration, while SSD use solid-state electronic memory chip arrays, welded to the circuit board, compared to HHD has lighter and thinner body and better shock tolerance.5. Power consumption and noiseHHD high-speed rotation of the disk requires a high-powered stepper motor to drive, while SSD do not require a motor to drive, so HHD in power consumption is much larger, working due to the rotation of the motor, there will be a small vibration and noise, while SSD are not these problems.How to choose:Need for speed: If you have specific requirements for storage speed, then you go for SSD.Gamers: Anyone who plays games knows that SSDs are a must, so SSDs are still a favorite for people who play games.Work travel: If you need to travel regularly for work, SSDs are certainly the first choice because they are small and have good shock resistance to ensure the safety of corporate data.General users: If you do not have extreme requirements for speed and do not need to carry it around, you can consider mechanical hard drivesSummary:1. From the appearance of the comparison of SSDs are much smaller than mechanical hard drives, conducive to notebooks to reduce the thickness.2. SSD do not have the motors used in mechanical hard drives and start up very fast. Because SSD do not need heads, the speed of reading is several times that of mechanical hard drives, even if the disk fragmentation will not affect the reading speed.3. SSDs do not have mechanical motors and electric fans, so there is no noise, HHD can be understood as a precision instrument, SSDs are an integrated circuit, so the shock resistance and temperature adaptability is higher than HHD.4. The high cost of SSD, and the capacity has been much lower than mechanical hard drives. Limited by the number of reads and writes, the service life of SSD is relatively short.5. Disk fragmentation does not affect the SSD read, but affects the disk write, the speed is lower than the HHD. More susceptible to external interference than mechanical hard drives, and data damage is difficult to repair.In terms of VPS hosting server, there are both SSD and HHD. Many providers just provide the VPS hosting server with HHD whose I/O speed is slow, LightNode&#x27;s VPSes all use SSD, you can get a high speed to transferring data.

Difference Between SSD and HHD

Другие статьи