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const obj = { 1: "a", 2: "b", 3: "c" }; const set = new Set([1, 2, 3, 4, 5]); obj.hasOwnProperty("1"); obj.hasOwnProperty(1); set.has("1"); set.has(1); A: false true false true B: false true true true C: true true false true D: true true true true Answer: C All object keys (excluding Symbols) will be stored as strings, even if you don't ...

Template syntax WXML is a set of tag language for framework design. Combined with basic components and event system, it can build the structure of the page Differences between WXML and HTML: text in WXML is equivalent to span in HTMLview in WXML is equivalent to div in HTMLCheckboxes in WXML are equivalent to checkbox es in HTML Data bindin ...

1, Self closing labels and notes Comments in HTML. The contents of comments will be ignored by the browser and will not be displayed directly in the web page, but you can view comments in the source code. Comments are used to explain the code. <!-- --> During development, we must develop a good habit of writing notes, which are requir ...

Data collection jsoup -jsoup introduction: 1. jsoup is a Java HTML parser, which can directly parse a URL address and HTML text content. 2. The main functions of jsoup are as follows: -Parsing HTML from a URL or string; -Use DOM or CSS selector to find and retrieve data; -Operable HTML elements, attributes and text; 3. jsoup is released based ...

tailwindcss official website (8) Customization: plug-ins, presets (presets, combined configuration) Official website: Installation - Tailwind CSS Chinese document Tailwind is a framework for building customized user interfaces, so customization is considered from the beginning of design.!important This property allows the browser ...

Rotation chart It is often located on the home page and used as a large picture for activity promotion. It can be played automatically by clicking the left and right switch button, or by clicking the small dot on the picture   Tab Toggle It is used to click different labels or titles to display different contents   Form Validation ...

In the development of fluent, we can reuse colors and descendants by defining themes, so as to make the design of the whole APP look more consistent 1. Use of theme theme Theme is divided into global theme and local theme Topics serve two purposes: After setting the theme, some widgets will automatically use the theme style (such a ...

Current limiting: it is solved by configuring sentinel Queue, asynchronous                       Through locking synchronized or lock, the problem is that the scope of synchronized is a single jvm instance, the cluster distribution fails, and the serial efficiency decreases after locking a single jvm Distributed locks can be used, but ...

I. PC-side web page effects 1.Element offset offset series 1.1 offset overview Offset is translated as an offset, and its position (offset), size, and so on can be dynamically obtained using the offset series related attributes. Get the distance of the element with the positioned parent elementGet the size (width and height) of the element ...

Packaging Number(), String(), and Boolean() are respectively "wrapper classes" for numeric, string, and Boolean values.Many programming languages have the design of "wrapper classes". The purpose of wrapper classes is to enable the basic type values to obtain methods from the prototype of their constructor. Summary of ...