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Reference link: W3school-JavaScript HTML DOM Reference article: Han_python blog JavaScript Column 14 Document object model Document Object Mode, referred to as DOM. When a web page is loaded, the browser creates the DOM of the page. It defines: HTML elements as objects, Attributes of HTML elements (can be set or changed) Method (action) t ...

Derived state of React Prior to react 16.3, the only way to update the state s inside a component when props changed was to use componentWillReceiveProps followed by a getDerivedStateFromProps. There are two scenarios when using a derived state: Manage a copy of the props passed by the parent component in the state of the child componen ...

Member of class     attribute         Static properties         Non static attribute     method         Static method         Non static method     constr ...

Throttling and anti chattering of JS Function debounce Basic concept: the callback is executed within n seconds after the time is triggered. If it is triggered again within n seconds, the timing will be restarted. Examples without anti shake function function inputChange(content) { console.log("inputContent" + content); } let input = ...

js question mark dot (?) - optional chain operator and double question mark (?) - usage of null value merging operator & deconstruction assignment: {data: {Name:'name '}} 1. Question mark dot (?) - optional chain operator The optional chain operator (?.) allows you to read the value of an attribute deep in the chain of connected objects w ...

String operation method 1. Convert to string type toString() (1)var num=110; var n=num.toString(); //"110" (2)var num=111; var n=String(num); //"111" (3)var num=112; var n="" + num; //"112" 2. String segmentation returns a new array split() (1)var str="qingchenghuwoguoxiansheng,woaishenghuo,woaiziji"; var arr1=str.split ...

1. What is shallow copy Create a new object that has an exact copy of the original object property values. If the attribute is a basic type, the value of the basic type is copied. If the attribute is a reference type, the memory address is copied  ， So if one object changes this address, it will affect the other object. Above, ` S ...

What is Promise.allSettled()! Novice and veteran? Promise.allSettled()   Method returns a statement that has been returned in all given promises   fulfilled   or   rejected   Posterior   Promise, with an array of objects, and each object represents the corresponding promise result. Next, let's take a look   ...

1. Variable declaration let is used to declare a variable A variable is not promoted, that is, it cannot be used until it is declared The declaration cannot be repeated It has a block level scope and is only valid in the current scope const is used to declare a constant The variable declaration is not promoted, that is, the variable can ...

This article will explain in detail   Prototype chain inheritance, constructor based inheritance (call method inheritance), combinatorial inheritance, parasitic combinatorial inheritance, class class class inheritance 1, Prototype chain inheritance Prototype chain inheritance is to assign a display prototype to the subclass constructor, ...