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Variable declaration Variable declaration Let and const are relatively new variable declarations in JavaScript. As we mentioned before, let is similar to var in many aspects, but it can help you avoid some common problems in JavaScript. Const is an enhancement to let, which can prevent the re assignment of a variable. Because TypeScript ...

Scope Scope is divided into local scope and global scope. Scope is often related to variables. Variables in the global scope can be accessed in the local scope, while variables in the local scope cannot be accessed outside the local scope. Look at an example of local scope accessing global scope // Local scope access global scope let glob ...

I. Introduction to SSM framework SSM framework is the acronym of Spring + Spring MVC + MyBatis. It is the mainstream Java EE enterprise framework after inheriting SSH. It is suitable for building various large-scale enterprise application systems. As shown in the figure: 1, What is Spring Spring is an open source framework. It is a ligh ...

Browser architecture JavaScript runs in the browser, BOM is the bridge between JavaScript code and browser, and DOM is used to operate various tag elements. BOM includes window, history, location, document DOM includes Document (whole Document), Element (label Element), CharacterData (character data) and Attr (attribute), which can be further d ...

📋 Personal profile 💖 About the author: Hello, I'm Daniel 😜📝 Personal homepage: Hall owner a Niu🔥🎉 Support me: like 👍+ Collection ⭐ Email + message 📝📣 Series column: web development🍁💬 Maxim: so far, all life is written with failure, but it doesn't prevent me from moving forward! 🔥 🍒 preface Today, I'd like to summari ...

catalogue 1, Definition of array 1.1 literal grammatical form 1.2 constructor definition form 2, Basic operation of array 2.1 calling 2.1 modification 2.3 NEW 3, Circular traversal of array 3.1 for...in 3.2 for...of 3.3 forEach 4, Function operation syntax of array ES5 4.1 array mapping 4.2 array filtering 4.3 array judgment 5 ...

Life cycle of vue The process of vue instance from creation to destruction is the life cycle. vue each component is independent, and each component has its own life cycle. Life cycle makes it easier for us to form better logic when controlling the whole vue. It can be divided into three stages: Mount stage, update stage and destroy stage. ...

Wechat applet various permission processing authorization logic, read this article is enough Let's see the effect first: This blog doesn't talk about Wx GetUserInfo's authorization allows and denies logic, only other permissions Starting from using the function, the detailed logical processing of authorization, refusal of authorization and ...

https://www.bilibili.com/video/BV1SE411H7CY Review of some js contents Array related methods length gets the number of elementspush add aftershift removes the element on the leftsplice(index,num) deletes elements. Where does index start to delete elements? num is how many elements are deleted Use js to select elements and bind click events ...

After the project is developed and launched, a series of preparations need to be made, including but not limited to: Compress CSS, JavaScript and HTML filesIf SASS or LESS is used, it needs to be compiled, otherwise the whole project cannot runSimilarly, if there is a version requirement for JavaScript, you also need to use babel to transl ...