How to get the first value in the select drop-down box in JavaScript-JS Tutorial-php.cn

Home

Web Front-end

JS Tutorial

How to get the first value in the select drop-down box in JavaScript

亚连

Jun 07, 2018 pm 02:43 PM

javascriptObtain

This article mainly introduces the JavaScript method to obtain the first value in the select drop-down box, involving JavaScript related acquisition operation skills for page element attributes. Friends in need can refer to the following

Examples of this article Use JavaScript to implement the method of getting the first value in the select drop-down box. Share it with everyone for your reference, the details are as follows:

1. Description

Get the first value in the select drop-down box

2. Implement the source code

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>JavaScript获取select下拉框中的第一个值</title>
<script type="text/javascript">
   /**
   * JavaScript获取select下拉框中的第一个值
   */
   function getFirstValOfSelect()
   {
     //获取select中的ID
     var selectId = document.getElementById("select_option");
     //获取select下拉框中第一个值
     var selectValue = selectId.options[0].value;
     //获取select下拉框中第一个文本值
     var selectText = selectId.options[0].text;
     //打印select下拉框中第一个值和文本值
     alert("值：" + selectValue + "\n" + "文本值：" + selectText);
   }
</script>
</head>
<body>
  <p id="p_select">
    <select id="select_option">
      <option value="0">桃树</option>
      <option value="1">梨树</option>
      <option value="2">樟树</option>
      <option value="3">枫树</option>
      <option value="4">松树</option>
      <option value="5">梧桐树</option>
      <option value="6">槐树</option>
    </select>
  </p>
  <input type="button" value="JavaScript获取select下拉框中的第一个值" onclick="getFirstValOfSelect()"/>
</body>
</html>

3. Implement the result

(1) Select the first item

(2) Select the second item

The above is what I compiled for everyone. I hope it will be helpful to everyone in the future.

Using Vue to implement the underlying principles (detailed tutorial)

How to implement dragging and obtaining control files in js Drag and drop content function

Detailed interpretation of the decorative design pattern in js

The above is the detailed content of How to get the first value in the select drop-down box in JavaScript. For more information, please follow other related articles on the PHP Chinese website!

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

Python vs. JavaScript: A Comparative Analysis for DevelopersMay 09, 2025 am 12:22 AM

The main difference between Python and JavaScript is the type system and application scenarios. 1. Python uses dynamic types, suitable for scientific computing and data analysis. 2. JavaScript adopts weak types and is widely used in front-end and full-stack development. The two have their own advantages in asynchronous programming and performance optimization, and should be decided according to project requirements when choosing.

Python vs. JavaScript: Choosing the Right Tool for the JobMay 08, 2025 am 12:10 AM

Whether to choose Python or JavaScript depends on the project type: 1) Choose Python for data science and automation tasks; 2) Choose JavaScript for front-end and full-stack development. Python is favored for its powerful library in data processing and automation, while JavaScript is indispensable for its advantages in web interaction and full-stack development.

Python and JavaScript: Understanding the Strengths of EachMay 06, 2025 am 12:15 AM

Python and JavaScript each have their own advantages, and the choice depends on project needs and personal preferences. 1. Python is easy to learn, with concise syntax, suitable for data science and back-end development, but has a slow execution speed. 2. JavaScript is everywhere in front-end development and has strong asynchronous programming capabilities. Node.js makes it suitable for full-stack development, but the syntax may be complex and error-prone.

JavaScript's Core: Is It Built on C or C ?May 05, 2025 am 12:07 AM

JavaScriptisnotbuiltonCorC ;it'saninterpretedlanguagethatrunsonenginesoftenwritteninC .1)JavaScriptwasdesignedasalightweight,interpretedlanguageforwebbrowsers.2)EnginesevolvedfromsimpleinterpreterstoJITcompilers,typicallyinC ,improvingperformance.

JavaScript Applications: From Front-End to Back-EndMay 04, 2025 am 12:12 AM

JavaScript can be used for front-end and back-end development. The front-end enhances the user experience through DOM operations, and the back-end handles server tasks through Node.js. 1. Front-end example: Change the content of the web page text. 2. Backend example: Create a Node.js server.

Python vs. JavaScript: Which Language Should You Learn?May 03, 2025 am 12:10 AM

Choosing Python or JavaScript should be based on career development, learning curve and ecosystem: 1) Career development: Python is suitable for data science and back-end development, while JavaScript is suitable for front-end and full-stack development. 2) Learning curve: Python syntax is concise and suitable for beginners; JavaScript syntax is flexible. 3) Ecosystem: Python has rich scientific computing libraries, and JavaScript has a powerful front-end framework.

JavaScript Frameworks: Powering Modern Web DevelopmentMay 02, 2025 am 12:04 AM

The power of the JavaScript framework lies in simplifying development, improving user experience and application performance. When choosing a framework, consider: 1. Project size and complexity, 2. Team experience, 3. Ecosystem and community support.

The Relationship Between JavaScript, C , and BrowsersMay 01, 2025 am 12:06 AM

Introduction I know you may find it strange, what exactly does JavaScript, C and browser have to do? They seem to be unrelated, but in fact, they play a very important role in modern web development. Today we will discuss the close connection between these three. Through this article, you will learn how JavaScript runs in the browser, the role of C in the browser engine, and how they work together to drive rendering and interaction of web pages. We all know the relationship between JavaScript and browser. JavaScript is the core language of front-end development. It runs directly in the browser, making web pages vivid and interesting. Have you ever wondered why JavaScr

See all articles