js operation secondary linkage implementation code_javascript skills
Second-level or multi-level linkage is mainly based on the table with parent number in the database, and this is no exception
Three columns of id, parent_id, name.
Using js operation
Let’s first talk about how data is stored in js.
Mainly use two-dimensional arrays to store data. The structure is as follows:
a[parent number]=[[child number 1, child name 1], [child number 2, child name 2], [child number 3, child name 3],…];
First, use the parent number to get all the child data, and then bind the number and name of the child data in dropdown
The first step is the second-level linkage data (how to get these data later)
var cities=new Array();
cities ['00000000-0000-0000-0000-000000000000']=[['028db215-8bd7-45ab-bbaa-1efa175c35ca','Changchun'],['bcb32195-2a46-4cd1-9472-6383e8fa55cc',' Shenyang'] ];
var schools=new Array();
schools['028db215-8bd7-45ab-bbaa-1efa175c35ca']=[['5f22403a-7a59-4b7f-b62d-9451298cbd00','Changchun 1'],['e8f0f665-9a9a-4c44-83fd-598e8a28dcd7','Changchun 2']]; -a44e-8d169d715664','Shenyang 1']];
The first level is city data, and the second level is school data. The second step is to set the data to be displayed in dropdown
//type=0 city, 1 school
//pid parent number
//obj to Dropdown to display data
function SetRegions(type,pid,obj)
{
var text="
In the third step, when the city changes, select school data
function CityChanged(){
SetRegions (1,$("#cities").val(),"#schools");
}
The fourth step is of course when modifying Initialization is required, which was also my biggest headache before
//cityId city number
//schoolId school number
function InitRegions(cityId,schoolId)
{
//Initialize city data
//SetRegions(0,"00000000-0000-0000-0000-000000000000","#cities");
//Find the city and set it as the default value
$("#cities option[value =" cityId "]").attr("selected","selected");
if(schoolId!="00000000-0000-0000-0000-000000000001"){
//Initialize school data
SetRegions(1,cityId,"#schools");
//Find a school and set it as the default value
$("#schools option[value=" schoolId "]").attr("selected", "selected");
}
}
Front-end code
<%--school--%>
Hot AI Tools
Undresser.AI Undress
AI-powered app for creating realistic nude photos
AI Clothes Remover
Online AI tool for removing clothes from photos.
Undress AI Tool
Undress images for free
Clothoff.io
AI clothes remover
Video Face Swap
Swap faces in any video effortlessly with our completely free AI face swap tool!
Hot Article
Hot Tools
Notepad++7.3.1
Easy-to-use and free code editor
SublimeText3 Chinese version
Chinese version, very easy to use
Zend Studio 13.0.1
Powerful PHP integrated development environment
Dreamweaver CS6
Visual web development tools
SublimeText3 Mac version
God-level code editing software (SublimeText3)
Hot Topics
What should I do if I encounter garbled code printing for front-end thermal paper receipts?
Apr 04, 2025 pm 02:42 PM
Frequently Asked Questions and Solutions for Front-end Thermal Paper Ticket Printing In Front-end Development, Ticket Printing is a common requirement. However, many developers are implementing...
Demystifying JavaScript: What It Does and Why It Matters
Apr 09, 2025 am 12:07 AM
JavaScript is the cornerstone of modern web development, and its main functions include event-driven programming, dynamic content generation and asynchronous programming. 1) Event-driven programming allows web pages to change dynamically according to user operations. 2) Dynamic content generation allows page content to be adjusted according to conditions. 3) Asynchronous programming ensures that the user interface is not blocked. JavaScript is widely used in web interaction, single-page application and server-side development, greatly improving the flexibility of user experience and cross-platform development.
Who gets paid more Python or JavaScript?
Apr 04, 2025 am 12:09 AM
There is no absolute salary for Python and JavaScript developers, depending on skills and industry needs. 1. Python may be paid more in data science and machine learning. 2. JavaScript has great demand in front-end and full-stack development, and its salary is also considerable. 3. Influencing factors include experience, geographical location, company size and specific skills.
How to merge array elements with the same ID into one object using JavaScript?
Apr 04, 2025 pm 05:09 PM
How to merge array elements with the same ID into one object in JavaScript? When processing data, we often encounter the need to have the same ID...
Is JavaScript hard to learn?
Apr 03, 2025 am 12:20 AM
Learning JavaScript is not difficult, but it is challenging. 1) Understand basic concepts such as variables, data types, functions, etc. 2) Master asynchronous programming and implement it through event loops. 3) Use DOM operations and Promise to handle asynchronous requests. 4) Avoid common mistakes and use debugging techniques. 5) Optimize performance and follow best practices.
How to achieve parallax scrolling and element animation effects, like Shiseido's official website?
or:
How can we achieve the animation effect accompanied by page scrolling like Shiseido's official website?
Apr 04, 2025 pm 05:36 PM
Discussion on the realization of parallax scrolling and element animation effects in this article will explore how to achieve similar to Shiseido official website (https://www.shiseido.co.jp/sb/wonderland/)...
The Evolution of JavaScript: Current Trends and Future Prospects
Apr 10, 2025 am 09:33 AM
The latest trends in JavaScript include the rise of TypeScript, the popularity of modern frameworks and libraries, and the application of WebAssembly. Future prospects cover more powerful type systems, the development of server-side JavaScript, the expansion of artificial intelligence and machine learning, and the potential of IoT and edge computing.
The difference in console.log output result: Why are the two calls different?
Apr 04, 2025 pm 05:12 PM
In-depth discussion of the root causes of the difference in console.log output. This article will analyze the differences in the output results of console.log function in a piece of code and explain the reasons behind it. �...
