• Relearning JavaScript in front end (5) related problems in JavaScript


    This article is mainly about some questions raised by winter and my thoughts. If there is something wrong, I hope you can point out it. 1Why do some programming specifications require void 0 instead of undefined?    this article mainly introduces the attribute descriptor in JavaScript, module in ES6 and arrow function. The value of […]

  • Learn more about JavaScript data types


    Data type is what we learnJavaScriptIt’s the first thing that you touch when you’re in loveJavaScriptThis knowledge seems simple, but in fact there are many beginners and even some of them have studied for many yearsJavaScriptIt’s something you don’t know. data type Ecsmascript standard specifies seven data types, which are divided into basic type and […]

  • HTML5 elements and basic grammar


    HTML tagOpening tag: open tagClosing tag: closing tag elementDefinition: HTML element refers to the code from the start tag to the end tag (the element starts with the start tag and ends with the end tag)Element content: element content refers to the content between the start tag and the end tag Characteristics of elements:1. Most […]

  • Realization of right triangle by CSS


    Mainstream browsers basically support it <div class=”triangle”></div> .triangle{ height: 200px; width: 200px; background-image: linear-gradient(to bottom right,red 50%, transparent 50%); }

  • Basic packaging types


    Basic wrapper type is to wrap simple data type into complex data type. var str = ‘andy’; console.log(str.length); Only objects and complex data types have attributes and methods. Why is there a length attribute? The process is as follows Var temp = new string (‘andy ‘); / / wrapped as complex data type STR = […]

  • Use of. Net core memorycache


        It seems that you can use it directly without nuget package. using Microsoft.Extensions.Caching.Memory;   public static class CacheHelperNetCore { public static IMemoryCache _memoryCache = new MemoryCache(new MemoryCacheOptions()); /// ///Set key value cache /// /// ///Value ///Expiration time public static void SetCache(string key,object obj,TimeSpan timeSpan) { _memoryCache.Set(key,obj,timeSpan); } /// ///Get key value cache /// […]

  • Weighted least squares in Statistical Science


    Today, we will talk about the weighted least squares (WLS), which is based on the ordinary least squares regression (OLS), and is mainly used to solve the heteroscedasticity problem. The general form of OLS is as follows: As we mentioned earlier, OLS has several basic assumptions. One of them is that UI is a random […]

  • Detailed record of project Upgrade — upgrade Vue project to webpack4 and babel7


    Project upgrade objectives: Original project: vue2 + webpack3 + babel6Upgrade project: vue2 + webpack4 + babel7 Recently, we need to upgrade the Vue project to get better construction performance and development convenience. As there is no practical article on the Internet for reference, we will record and share the process of upgrading the project with […]

  • More than a dozen lines of code to teach you to achieve the simplest version of promise


    Recently, I studied the implementation of promise. This article uses more than ten lines of code to implement a simple promise, so as to help readers have a deeper understanding of promise ‘. The promise implemented in this article is promises / A +. When reading this article, it has been assumed that you know […]

  • Webpack learning notes (5): plugins configuration


    Plugins is another important function of webpack. Why use plugins The function of plugins is to expand the function of webpack. It will take effect in the whole process of project construction and perform related tasks. The difference between plugins and loaders is that loaders are used to process source files (for example, JSX, sass, […]

  • Some learning process of PHP to go


    php My first contact with programming was in 2016. At that time, I learned PHP out of my personal hobbies and in order to subsidize some living expenses. I was responsible for the construction and maintenance of the school’s websites, large and small. During this period, I was basically working in the UniversityimoocIt took half […]