How to Make JSONP Requests in JavaScript Without External Libraries?

Creating JSONP Requests in JavaScript Without External Libraries

For cross-domain requests, JSONP (JSON with Padding) allows retrieval of data from a different domain. Instead of relying on external libraries like jQuery, JavaScript can accomplish this natively.

To initiate a JSONP request:

1. Create a Callback Function:
   Write a JavaScript function, in this case "foo", that will be called with the requested data.
2. Construct the Request URL:
   Formulate the JSONP request URL with the appropriate endpoint, parameters, and callback function name. This URL will typically end with "?callback=foo".
3. Create a Script Element:
   Dynamically generate a script element using JavaScript's DOM. Set the "src" attribute of this element to the JSONP request URL.
4. Append Script to Document:
   Append the newly created script element to the HTML document's element. This action will automatically trigger the request.

Example Code:

function foo(data) {
    // Process and utilize the JSON data
}

var script = document.createElement('script');
script.src = '//example.com/path/to/jsonp?callback=foo';

document.head.appendChild(script);

By employing these steps, you effectively initiate a JSONP request without external libraries, allowing you to retrieve cross-domain JSON data and process it within your JavaScript code.

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