ajax request data to javascript

Today, web development has become an integral part of modern life and business. With the continuous development of technology and user needs, JavaScript and AJAX have become one of the two most important technologies indispensable in web development.

JavaScript is a programming language used to create interactive Web pages. The language is a scripting language that injects interactivity into web pages and can be used with other technologies such as HTML and CSS. It enables users to enjoy richer and more dynamic digital experiences.

On the other hand, AJAX (Asynchronous JavaScript and XML) is a technology that uses JavaScript, XML and HTTP technologies to create interactive web pages. Unlike traditional web pages, AJAX enables data interaction and content updates without completely refreshing the web page. The emergence of this technology makes web pages faster, more efficient and more convenient.

Today, we’ll dive into how to request data in AJAX and pass them to JavaScript. Here are some basic steps to request data using AJAX:

1. Creating an XMLHttpRequest object
   In AJAX, the XMLHttpRequest object is used to request data from the server. In JavaScript, you can create an XMLHttpRequest object in the following way:

var xhttp = new XMLHttpRequest();

2. Open the server request
   After creating the XMLHttpRequest object, you need to set the request type, URL and whether to make an asynchronous request. Use the following code to open and send the request:

xhttp.open("GET", "url", true);
xhttp.send();

3. Get response data
   After sending the request, you need to use the onreadystatechange event to handle the server response so that after receiving the server response Take appropriate action. The following is a simple onreadystatechange event handler:

xhttp.onreadystatechange = function() {
    if (this.readyState == 4 && this.status == 200) {
        // do something with the response data
    }
};

With this event handler, you can check the status and HTTP status code of the response. If the response is successful, the data can be manipulated.

4. Parse the response data and pass them to JavaScript
   When you get the response data, you must parse the response data and pass them to JavaScript for processing. The method of parsing response data depends on the response type. For example, if the response type is XML, you can use an XML DOM object to parse the response data as follows:

var xmlDoc = xhttp.responseXML;

Alternatively, if the response type is JSON, you can use JSON.parse() to Parsing the response data:

var jsonData = JSON.parse(xhttp.responseText);

Regardless of the method used, the parsed data must be passed to JavaScript for processing.

Overall, AJAX is a powerful tool that provides web developers with new levels of interactivity and performance. If you haven't started using AJAX yet, now is the time to learn and apply it to your web projects.

The above is the detailed content of ajax request data to javascript. For more information, please follow other related articles on the PHP Chinese website!