jquery changes the value of the label text box

With the development of the Internet, the functions of websites are becoming more and more abundant. In web development, jQuery is a commonly used JavaScript library. It provides a rich API that allows us to process DOM elements and page interactions more quickly and conveniently.

This article will mainly introduce how to use jQuery to change the value of the label text box. In many websites, pages need to dynamically display or hide some content, change page layout, etc. based on user input. These functions need to be implemented by modifying the value of the text box. Therefore, the content of this article will help developers better understand and master the use of jQuery.

1. Understand the type of text box

Before we start using jQuery to modify the value of the text box, we need to first understand the type of the text box. There are two types of text boxes in HTML: input and textarea. Among them, input is divided into different types, such as text, password, email, checkbox, etc. Each type of text box has its special properties and methods, so when we use jQuery to modify the text box value, we need to handle it accordingly according to different types.

2. Use jQuery to select a text box

In jQuery, you can easily select a text box through the selector. For example, to select a text box with the id "username", you can use the following code:

$("#username")

Among them, $ means using the abbreviation of jQuery, # means selecting the id, so "#username" means selecting the id "username" "Elements. If you use class to select a text box, you can use the following code:

$(".text-input")

Among them, ".text-input" means selecting all elements whose class attribute is "text-input". If you want to select a certain type of text box, you can use the following code:

$("input[type='text']")

Among them, "input[type='text']" means to select all input elements whose type attribute is "text".

3. Modify the value of the text box

After selecting the text box, you can modify its value through jQuery. For example, to change the value of a text box with the ID "username" to "Zhang San", you can use the following code:

$("#username").val("张三");

Among them, val() is a method provided by jQuery, which can get or set a text The value of the box. If there are no parameters, the value of the text box is obtained; if there are parameters, the value of the text box is set.

If multiple text boxes are selected, you can use the each() method to traverse them and perform corresponding operations on each element. For example, to set the values ​​of all text boxes of type "text" to "default value", you can use the following code:

$("input[type='text']").each(function(){
   $(this).val("默认值");
});

Among them, $(this) represents the currently traversed element, val(" Default value") is to set the value of the element to the "default value".

4. Summary

Through the introduction of this article, we have learned about the types of text boxes and how to use jQuery to select and modify the value of the text box. In development, it is often necessary to achieve some dynamic effects by modifying the value of the text box, so it is very important to be proficient in these contents.

Of course, jQuery provides more than just the function of modifying the value of the text box. There are many other APIs that can help us better develop Web applications. I hope this article will inspire readers. More jQuery-related knowledge can be learned through official documents, blogs, books, etc.

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