Understanding the five common Ajax submission methods

To understand the five commonly used submission methods of AJAX, specific code examples are required

AJAX (Asynchronous JavaScript and XML) is a method used to create interactive web applications. technology. It allows partial page content to be updated through asynchronous communication with the server without refreshing the entire page. AJAX is widely used in modern web development to provide users with a better interactive experience.

In AJAX, data submission is a very important part. The following will introduce the five commonly used AJAX submission methods, as well as specific code examples for each method.

1. Submitting data by GET method:
   GET is one of the most common HTTP request methods. It appends parameters to the end of the URL and passes them to the server in the form of key-value pairs. The GET method is suitable for obtaining data, but it is not suitable for handling sensitive information. The following is a code example that uses GET to submit data:

var xmlhttp = new XMLHttpRequest();
var url = "server.php?name=John&age=20";
xmlhttp.open("GET", url, true);
xmlhttp.send();

2. Submit data through POST:
   POST is another common HTTP request method, which sends data parameters to in the server's request body. Compared with the GET method, the POST method is more suitable for handling sensitive information because the data will not be displayed in the URL. The following is a code example that uses the POST method to submit data:

var xmlhttp = new XMLHttpRequest();
var url = "server.php";
var params = "name=John&age=20";
xmlhttp.open("POST", url, true);
xmlhttp.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
xmlhttp.onreadystatechange = function() {
  if (xmlhttp.readyState == 4 && xmlhttp.status == 200) {
    // 请求成功后的处理逻辑
    console.log(xmlhttp.responseText);
  }
};
xmlhttp.send(params);

3. FormData method submits data:
   FormData is a built-in JavaScript object used to create form data. It can construct form data by adding key/value pairs and send it to the server. The following is a code example for submitting data using the FormData method:

var xmlhttp = new XMLHttpRequest();
var url = "server.php";
var formData = new FormData();
formData.append("name", "John");
formData.append("age", "20");
xmlhttp.open("POST", url, true);
xmlhttp.onreadystatechange = function() {
  if (xmlhttp.readyState == 4 && xmlhttp.status == 200) {
    // 请求成功后的处理逻辑
    console.log(xmlhttp.responseText);
  }
};
xmlhttp.send(formData);

4. Submitting data using the JSON method:
   JSON (JavaScript Object Notation) is a lightweight data exchange format. It is also a data format commonly used in AJAX. JSON data can be converted from JavaScript objects to JSON strings through the JSON.stringify() method and sent to the server through POST. The following is a code example for submitting data using JSON:

var xmlhttp = new XMLHttpRequest();
var url = "server.php";
var data = {name: "John", age: 20};
xmlhttp.open("POST", url, true);
xmlhttp.setRequestHeader("Content-type", "application/json");
xmlhttp.onreadystatechange = function() {
  if (xmlhttp.readyState == 4 && xmlhttp.status == 200) {
    // 请求成功后的处理逻辑
    console.log(xmlhttp.responseText);
  }
};
xmlhttp.send(JSON.stringify(data));

5. Submitting data using XML:
   In some cases, it is necessary to use XML data format to submit data. In AJAX, this can be achieved by creating XMLHttpRequest objects and manipulating XML data. The following is a code example for submitting data using XML:

var xmlhttp = new XMLHttpRequest();
var url = "server.php";
var xmlData = '<?xml version="1.0" encoding="UTF-8"?><data><name>John</name><age>20</age></data>';
xmlhttp.open("POST", url, true);
xmlhttp.setRequestHeader("Content-type", "text/xml");
xmlhttp.onreadystatechange = function() {
  if (xmlhttp.readyState == 4 && xmlhttp.status == 200) {
    // 请求成功后的处理逻辑
    console.log(xmlhttp.responseText);
  }
};
xmlhttp.send(xmlData);

The above are specific code examples of the five commonly used AJAX submission methods. By understanding and practicing these submission methods, you can better use AJAX technology to process data and improve the user experience of your web applications.

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