Same-Origin AJAX Request Using Vanilla JavaScript

This JavaScript function will send an AJAX request – GET or POST – with no third-party dependencies:

function soQuery(soMethod, soUri) {
    var xhttp = new XMLHttpRequest();

    xhttp.open(soMethod, soUri, true);

    if (soMethod === 'GET') {
        xhttp.send();
    } else if (soMethod === 'POST') {
        xhttp.setRequestHeader('Content-type', 'application/x-www-form-urlencoded');
        xhttp.onload = function () {
            // do something to response
            console.log(this.responseText);
        };
        xhttp.send('param1=param1value&param2=param2value&param3=param3value');
    }
}

// Usage
soQuery('GET', 'https://www.example.com/query.php');

Note that the URL should be on the same domain as the function caller.

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