Detailed explanation of how to delete each other between PHP and JavaScript

PHP and JavaScript are two programming languages ​​that both play important roles in web development. PHP is used to handle server-side logic, while JavaScript is used to handle client-side logic. In web development, it is often necessary to dynamically display, hide, add, and delete HTML elements, and PHP and JavaScript have their own unique methods to implement these operations. However, in some cases, we need to use PHP to delete elements in JavaScript code, or use JavaScript to delete elements in PHP code. This article will introduce how to delete each other in PHP and JavaScript.

1. Delete JavaScript elements in PHP

In PHP, we can use string manipulation functions to process JavaScript code. We can use the preg_replace() function to delete elements in JavaScript code. The preg_replace() function can replace the specified pattern in a string. When we pass JavaScript code to the preg_replace() function, it searches and replaces the parts that match the rules. We can use regular expressions to find elements to remove.

For example, if we want to delete the p element in the JavaScript code, we can use the following code:

$js_code = '
function test() {

var p = document.createElement("p");
document.body.appendChild(p);

}
';

$js_code = preg_replace('/document\.body\.appendChild\(p\);/', '', $js_code);

echo $js_code ;

In the above code, we use the preg_replace() function and pass a regular expression as the first parameter. The regular expression will match the line of code document.body.appendChild(p);. We remove this line of code by replacing it with an empty string. Finally, we output the removed JavaScript code to the screen.

2. Delete PHP elements in JavaScript

In JavaScript, we can use AJAX to communicate with the server. We can use the XMLHttpRequest object to send an HTTP request to the server and receive the response returned by the server. When we send a request to the server, we can pass the ID of the PHP element that needs to be removed as a parameter to the server. The server will delete this element from the database or file based on the ID, and then return the deleted result to the client.

Here is a simple example that demonstrates how to use AJAX to delete elements in PHP code.

HTML code:

<p id="p1">这是一个段落。</p>
<p id="p2">这也是一个段落。</p>
<button onclick="deleteElement()">删除段落</button>

JavaScript code:

function deleteElement() {

var xhttp = new XMLHttpRequest();
var id = "p1";
var url = "delete_element.php?id=" + id;
xhttp.onreadystatechange = function() {
    if (this.readyState == 4 && this.status == 200) {
        document.getElementById("container").innerHTML = this.responseText;
    }
}
xhttp.open("GET", url, true);
xhttp.send();

}

delete_element.php code:

$id = $_GET['id'];
$content = file_get_contents('elements.php');
$content = preg_replace('/

.*

/', '', $content);
echo $content;
?>

In the above example, we defined a deleteElement() function that is called when the user clicks the button. This function will send an HTTP GET request to the server and pass the ID of the element that needs to be deleted as a parameter to the server. The server will delete the corresponding element from the elements.php file based on the ID, and then return the deleted result to the client. Finally, the client uses the innerHTML attribute to update the content of the container element, achieving the effect of dynamically adding and deleting elements.

Summary

Both PHP and JavaScript can be used to handle logic in web development. In some cases, we need to use them with each other to achieve the effect of dynamically adding and removing elements. This article introduces how to delete each other between PHP and JavaScript. I hope it can be helpful to web developers.

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