How to traverse backend array with ajax in php

Using AJAX to achieve data interaction in PHP is a very common way. Send a request to the backend through your front-end code. The backend uses the PHP code to process an array, and then passes the array to the front-end through AJAX. . But how can I iterate over this backend array in a proper way in the frontend JS code?

1. Convert an array in PHP to a JSON string

To convert an array into a JSON string in PHP, you can use the json_encode() function:

$data = array("name"=>"John", "age"=>30, "city"=>"New York");
$json = json_encode($data);
echo $json;

In the output, we will see something like this:

{"name":"John","age":30,"city":"New York"}

This string represents an object containing a name, age, and city.

2. Get JSON data through AJAX in the front-end code

In the front-end code, we usually use the XHR object or the AJAX method encapsulated in libraries such as jQuery to obtain JSON data.

The following is a code example that uses the When the client obtains a JSON array, you can use the forEach() method in JavaScript to iterate through each element in the array.

The following is a sample code that uses the forEach() method to traverse a JSON array:

3. var xhr = new XMLHttpRequest();
   xhr.open('GET', 'url-to-php-file.php', true);
   xhr.onreadystatechange = function() {
     if(xhr.readyState === 4 && xhr.status === 200) {
       // 处理返回的 JSON 数据
       var json = JSON.parse(xhr.responseText);
       // 遍历数组等操作
       // ...
     }
   }
   xhr.send();

For a JSON data returned from the PHP backend, you only need to parse it into a JavaScript object and pass it Just traverse the method to access its contents.

If the JSON data contains nested arrays, you can use recursion to traverse the entire data structure.

Summary:

The above are the general steps and several simple methods on how to traverse the backend array in the front-end code when using AJAX to implement array interaction in PHP. By converting PHP arrays into JSON strings and passing the data to the front-end through AJAX objects, we can use JavaScript arrays and traversal functions in the front-end to easily access the data passed by the back-end.

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