JavaScript date selection function example_javascript skills
This article mainly introduces the JavaScript date selection function, and analyzes the JavaScript date and time related operation skills in the form of examples. Friends in need can refer to it
This article describes the JavaScript date selection function with examples. Share it with everyone for your reference, the details are as follows:
<html xmlns="http://www.w3.org/1999/xhtml"> <head> <meta charset="utf-8"> <title>javascript日期选择</title> <style type="text/css"> option{ width:150px; } </style> </head> <body> <!--<input type="hidden" value="window.location.href" />--> <br /> <p id="dateOp"> <select id="selectYear" onchange="getDay()"></select>年 <select id="selectMonth" onchange="getDay()"></select>月 <select id="selectDay"></select>日 <input type="button" value="getdate" /> </p> <script type="text/javascript"> //或得当前年月日 var date = new Date(); var year = date.getFullYear(); var month = date.getMonth() + 1; var day = date.getDate(); var startYear = 2000; var endYear = 2050; var button = document.getElementsByTagName("input")[0]; //得到三个select项 var selectYearElement = document.getElementById("selectYear"); var selectMonthElement = document.getElementById("selectMonth"); var selectDayElement = document.getElementById("selectDay"); //selectYearElement.onchange = getDay(); //selectMonthElement.onchange = getDay(); //selectYearElement.addEventListener getYear(); getMonth(); getDay(); //年份函数 function getYear() { for (var i = startYear; i <= endYear; i++) { var opYearElement = document.createElement("option"); var textElement = document.createTextNode(i); opYearElement.appendChild(textElement); opYearElement.value = i; selectYearElement.appendChild(opYearElement); } //设置默认年份的值 selectYearElement.selectedIndex = year - startYear; } //月份函数 function getMonth() { for (var i = 1; i <= 12; i++) { var opMonthElement = document.createElement("option"); textMonth = document.createTextNode(i); opMonthElement.appendChild(textMonth); opMonthElement.value = i; selectMonthElement.appendChild(opMonthElement); } //设置默认年份的值 selectMonthElement.selectedIndex = month - 1; } //日期函数 function getDay() { var getSelectedYear = selectYearElement.selectedIndex + startYear; var getSelectedMonth = selectMonthElement.selectedIndex + 1; var flag = 0; var selectDayElement = document.getElementById("selectDay"); if (selectDayElement.hasChildNodes()) { var optionElements = selectDayElement.getElementsByTagName("option"); for (var i = 0; i < optionElements.length; i++) { selectDayElement.removeChild(optionElements[0]); //不知道为什么必须得自减一 i--; } } else { } //得到闰年 if ((getSelectedYear % 4 == 0 && getSelectedYear % 100 != 0) || getSelectedYear % 400 == 0) {//得到闰年的年号 //alert("闰年"); //得到闰年大月份除二月以外 if ((getSelectedMonth <= 7 && getSelectedMonth % 2 == 1 && getSelectedMonth != 2) || (getSelectedMonth >= 8 && getSelectedMonth % 2 == 0)) {//得到大月 setDay(flag = 31); } else if (getSelectedMonth <= 7 && getSelectedMonth == 2) { setDay(flag = 29); } else if ((getSelectedMonth <= 7 && getSelectedMonth % 2 == 0 && getSelectedMonth != 2) || (getSelectedMonth >= 8 && getSelectedMonth % 2 == 1)) {//得到小月份除二月以外 setDay(flag = 30); } } //非闰年 else { //alert("平年"); //得到平年大月份除二月以外 if ((getSelectedMonth <= 7 && getSelectedMonth % 2 == 1 && getSelectedMonth != 2) || (getSelectedMonth >= 8 && getSelectedMonth % 2 == 0)) {//得到大月 setDay(flag = 31); } else if (getSelectedMonth <= 7 && getSelectedMonth == 2) { setDay(flag = 28); } else if ((getSelectedMonth <= 7 && getSelectedMonth % 2 == 0 && getSelectedMonth != 2) || (getSelectedMonth >= 8 && getSelectedMonth % 2 == 1)) {//得到小月份除二月以外 setDay(flag = 30); } } } //设置默认年份的值 selectDayElement.selectedIndex = day - 1; function setDay(dayLength) { for (var i = 1; i <= dayLength; i++) { var opDayElement = document.createElement("option"); textMonth = document.createTextNode(i); opDayElement.appendChild(textMonth); opDayElement.value = i; //alert(i); selectDayElement.appendChild(opDayElement); } } button.onclick = function () { var getSelectedYear = selectYearElement.selectedIndex + startYear; var getSelectedMonth = selectMonthElement.selectedIndex + 1; var getSelectedDay = selectDayElement.selectedIndex + 1; alert("当前选中的日期是:" + getSelectedYear + "年" + getSelectedMonth + "月" + getSelectedDay + "日") } //getDay </script> </body> </html>
The operation effect diagram is as follows:

Python and JavaScript have their own advantages and disadvantages in terms of community, libraries and resources. 1) The Python community is friendly and suitable for beginners, but the front-end development resources are not as rich as JavaScript. 2) Python is powerful in data science and machine learning libraries, while JavaScript is better in front-end development libraries and frameworks. 3) Both have rich learning resources, but Python is suitable for starting with official documents, while JavaScript is better with MDNWebDocs. The choice should be based on project needs and personal interests.

The shift from C/C to JavaScript requires adapting to dynamic typing, garbage collection and asynchronous programming. 1) C/C is a statically typed language that requires manual memory management, while JavaScript is dynamically typed and garbage collection is automatically processed. 2) C/C needs to be compiled into machine code, while JavaScript is an interpreted language. 3) JavaScript introduces concepts such as closures, prototype chains and Promise, which enhances flexibility and asynchronous programming capabilities.

Different JavaScript engines have different effects when parsing and executing JavaScript code, because the implementation principles and optimization strategies of each engine differ. 1. Lexical analysis: convert source code into lexical unit. 2. Grammar analysis: Generate an abstract syntax tree. 3. Optimization and compilation: Generate machine code through the JIT compiler. 4. Execute: Run the machine code. V8 engine optimizes through instant compilation and hidden class, SpiderMonkey uses a type inference system, resulting in different performance performance on the same code.

JavaScript's applications in the real world include server-side programming, mobile application development and Internet of Things control: 1. Server-side programming is realized through Node.js, suitable for high concurrent request processing. 2. Mobile application development is carried out through ReactNative and supports cross-platform deployment. 3. Used for IoT device control through Johnny-Five library, suitable for hardware interaction.

I built a functional multi-tenant SaaS application (an EdTech app) with your everyday tech tool and you can do the same. First, what’s a multi-tenant SaaS application? Multi-tenant SaaS applications let you serve multiple customers from a sing

This article demonstrates frontend integration with a backend secured by Permit, building a functional EdTech SaaS application using Next.js. The frontend fetches user permissions to control UI visibility and ensures API requests adhere to role-base

JavaScript is the core language of modern web development and is widely used for its diversity and flexibility. 1) Front-end development: build dynamic web pages and single-page applications through DOM operations and modern frameworks (such as React, Vue.js, Angular). 2) Server-side development: Node.js uses a non-blocking I/O model to handle high concurrency and real-time applications. 3) Mobile and desktop application development: cross-platform development is realized through ReactNative and Electron to improve development efficiency.

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.


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

AI Hentai Generator
Generate AI Hentai for free.

Hot Article

Hot Tools

SublimeText3 Chinese version
Chinese version, very easy to use

SAP NetWeaver Server Adapter for Eclipse
Integrate Eclipse with SAP NetWeaver application server.

Dreamweaver Mac version
Visual web development tools

Safe Exam Browser
Safe Exam Browser is a secure browser environment for taking online exams securely. This software turns any computer into a secure workstation. It controls access to any utility and prevents students from using unauthorized resources.

MinGW - Minimalist GNU for Windows
This project is in the process of being migrated to osdn.net/projects/mingw, you can continue to follow us there. MinGW: A native Windows port of the GNU Compiler Collection (GCC), freely distributable import libraries and header files for building native Windows applications; includes extensions to the MSVC runtime to support C99 functionality. All MinGW software can run on 64-bit Windows platforms.