The problem of callback function in jquery, prawn can help solve it~_html/css

Home

Web Front-end

HTML Tutorial

The problem of callback function in jquery, prawn can help solve it~_html/css_WEB-ITnose

WBOYWBOYWBOYWBOYWBOYWBOYWBOYWBOYWBOYWBOYWBOYWBOYWB

Jun 24, 2016 pm 12:03 PM

jqueryfunctionsolve

<!DOCTYPE html><html lang="en"><head><meta charset="utf-8" /><script src="jquery-1.9.1.min.js" type="text/javascript"></script><script type="text/javascript" >$(function(){    var t = [];    var dt = $("dl.collapse dt");    var dd = $("dl.collapse dd");    dt.each(function(i){        t[i] = false;        $(dt[i]).click((function(i,dd){            return function(){                if( t[i]){                    $(dd).show();                    t[i]  = false;                }                else{                    $(dd).hide();                    t[i]  = true;                }            }        })(i,dd[i]));                   })})</script><style type="text/css">.collapse { border:solid 1px #ccc; margin:2px; float:left; }.collapse dt { padding:8px 8px; background:#7FECAD url(green.gif) repeat-x; font-size:13px; font-weight:bold; color:#71790C; border-bottom:solid 1px #efefef; cursor:pointer; }.collapse dd { margin:0; padding:6px; }.w1 {width:310px;}.w2 {width:221px;}.w3 {width:665px;}</style><title>上机练习</title></head><body><dl class="collapse w1">    <dt>音乐标签</dt>    <dd><img  src="/static/imghwm/default1.png"  data-src="mp31.jpg"  class="lazy"   / alt="The problem of callback function in jquery, prawn can help solve it~_html/css_WEB-ITnose" ></dd></dl><dl class="collapse w2">    <dt>新歌TOP100</dt>    <dd><img  src="/static/imghwm/default1.png"  data-src="mp32.jpg"  class="lazy"   / alt="The problem of callback function in jquery, prawn can help solve it~_html/css_WEB-ITnose" ></dd></dl><dl class="collapse w3">    <dt>音乐掌门人</dt>    <dd><img  src="/static/imghwm/default1.png"  data-src="mp33.jpg"  class="lazy"   / alt="The problem of callback function in jquery, prawn can help solve it~_html/css_WEB-ITnose" ></dd></dl></body></html>

green.gif:
mp31.jpg:
mp32.jpg:
mp33.jpg:

I want to ask about this code :

$(dt[i]).click((function(i,dd){            return function(){                if( t[i]){                    $(dd).show();                    t[i]  = false;                }                else{                    $(dd).hide();                    t[i]  = true;                }            }        })(i,dd[i]));

What is the function of return?
Why not change it to the following?

$(dt[i]).click((function(i,dd){                if( t[i]){                    $(dd).show();                    t[i]  = false;                }                else{                    $(dd).hide();                    t[i]  = true;                }        })(i,dd[i]));

Reply to the discussion ( Solution)

Click binding must be a function. After you modify it, it will become a function that is automatically executed when it comes up. This is definitely wrong

And because of the problem of i scope, use Closure solves the i index problem, and finally returns the function to click

One is to pass the function, the one you wrote is executed directly, the difference is so big

After two people’s guidance, I already understand~thank you

Statement

The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn

Beyond HTML: Essential Technologies for Web DevelopmentApr 26, 2025 am 12:04 AM

To build a website with powerful functions and good user experience, HTML alone is not enough. The following technology is also required: JavaScript gives web page dynamic and interactiveness, and real-time changes are achieved by operating DOM. CSS is responsible for the style and layout of the web page to improve aesthetics and user experience. Modern frameworks and libraries such as React, Vue.js and Angular improve development efficiency and code organization structure.

What are boolean attributes in HTML? Give some examples.Apr 25, 2025 am 12:01 AM

Boolean attributes are special attributes in HTML that are activated without a value. 1. The Boolean attribute controls the behavior of the element by whether it exists or not, such as disabled disable the input box. 2.Their working principle is to change element behavior according to the existence of attributes when the browser parses. 3. The basic usage is to directly add attributes, and the advanced usage can be dynamically controlled through JavaScript. 4. Common mistakes are mistakenly thinking that values need to be set, and the correct writing method should be concise. 5. The best practice is to keep the code concise and use Boolean properties reasonably to optimize web page performance and user experience.

How can you validate your HTML code?Apr 24, 2025 am 12:04 AM

HTML code can be cleaner with online validators, integrated tools and automated processes. 1) Use W3CMarkupValidationService to verify HTML code online. 2) Install and configure HTMLHint extension in VisualStudioCode for real-time verification. 3) Use HTMLTidy to automatically verify and clean HTML files in the construction process.

HTML vs. CSS and JavaScript: Comparing Web TechnologiesApr 23, 2025 am 12:05 AM

HTML, CSS and JavaScript are the core technologies for building modern web pages: 1. HTML defines the web page structure, 2. CSS is responsible for the appearance of the web page, 3. JavaScript provides web page dynamics and interactivity, and they work together to create a website with a good user experience.

HTML as a Markup Language: Its Function and PurposeApr 22, 2025 am 12:02 AM

The function of HTML is to define the structure and content of a web page, and its purpose is to provide a standardized way to display information. 1) HTML organizes various parts of the web page through tags and attributes, such as titles and paragraphs. 2) It supports the separation of content and performance and improves maintenance efficiency. 3) HTML is extensible, allowing custom tags to enhance SEO.

The Future of HTML, CSS, and JavaScript: Web Development TrendsApr 19, 2025 am 12:02 AM

The future trends of HTML are semantics and web components, the future trends of CSS are CSS-in-JS and CSSHoudini, and the future trends of JavaScript are WebAssembly and Serverless. 1. HTML semantics improve accessibility and SEO effects, and Web components improve development efficiency, but attention should be paid to browser compatibility. 2. CSS-in-JS enhances style management flexibility but may increase file size. CSSHoudini allows direct operation of CSS rendering. 3.WebAssembly optimizes browser application performance but has a steep learning curve, and Serverless simplifies development but requires optimization of cold start problems.

HTML: The Structure, CSS: The Style, JavaScript: The BehaviorApr 18, 2025 am 12:09 AM

The roles of HTML, CSS and JavaScript in web development are: 1. HTML defines the web page structure, 2. CSS controls the web page style, and 3. JavaScript adds dynamic behavior. Together, they build the framework, aesthetics and interactivity of modern websites.

The Future of HTML: Evolution and Trends in Web DesignApr 17, 2025 am 12:12 AM

The future of HTML is full of infinite possibilities. 1) New features and standards will include more semantic tags and the popularity of WebComponents. 2) The web design trend will continue to develop towards responsive and accessible design. 3) Performance optimization will improve the user experience through responsive image loading and lazy loading technologies.

See all articles