Detailed explanation of javascript input method

The input() method in JavaScript is a simple way to obtain user input. It allows you to get a value from the user in a JavaScript program and store it in a variable. This article will introduce the input() method in detail and provide sample code for using it.

Input() method overview

Before using the input() method, you need to understand another method in JavaScript-prompt(). The prompt() method displays a dialog box containing a text input box and confirm/cancel buttons. There the user can enter text and press the confirm button to pass the value to the JavaScript program.

In contrast, the input() method creates an HTML input element in a Web page, allowing users to enter text directly into the page. This input element can be any type of form element such as text box, radio button, check box, drop-down list, etc. The syntax of the input() method is as follows:

input(type, promptText, defaultText, callback)

The meaning of each parameter is:

• type: indicates the type of input element, which can be "text" or "password" , "checkbox", "radio", "range", "color", "date", etc.
• promptText: Represents the prompt text of the input element.
• defaultText: Represents the default text of the input element. If the user does not enter anything, this text is used by default.
• callback: Indicates the specified callback function. When the user completes the input and presses the Enter key, the function will be called and the value entered by the user will be passed.

Note: This method returns a reference to the HTML input element, which can be used to further manipulate the element.

input() method example

Here is a simple example that demonstrates how to use the input() method to get text input from the user and store it in a variable:

let userName = input('text', '请输入您的姓名：', '张三', function (value) {
    console.log('欢迎您，' + value + '！');
});

In this example, we first define a variable named "userName" and initialize it to the return value of the input() method. Then, we specified the input element type as "text" in the method, the prompt text as "Please enter your name:", the default text as "Zhang San", and specified a callback function. The callback function will be called when the user completes the input and presses the Enter key, passing the user input value as a parameter to the function.

When considering the use of the input() method, you also need to pay attention to the following points:

• When the user presses the Enter key, the callback function will be called. In the callback function, you can do anything based on the user's input value, such as storing it in a variable, doing calculations, etc.
• The input element created by the input() method is displayed on the page and the user can interact with it. Therefore, you need to consider the appropriate location and time to call the input() method to maximize user privacy and security.
• The input() method only applies to browser environments and cannot be used in server-side JavaScript code.

Conclusion

The input() method is a convenient way to obtain input values ​​from the user. Whether it's a text input, a select button, or a drop-down list, this method creates the corresponding input element. The default callback function for a cancel or confirm button is automatically called when the user completes input. In addition, this method provides some additional properties to help you better adjust the appearance and behavior of the input element you create.

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