Typical Syntax Call

<script type="text/javascript"> 

    let URL = 'https://xxx.xxx.xxx.xxx/service.php'
    let sPlugin = "plugin";
    //
    const data = {  "configuration": [sPlugin, "action", "extra"],
	                    'word': ' Απόδειξη ',
	};
    //
    fetch(URL, {    method: "POST",   body: JSON.stringify(data),
	headers: {   "Content-type": "application/json;
		 charset=UTF-8"    
		}
	}).then(response => response.json())
        .then(dataRet => {
	            const returnJSON = JSON.parse(dataRet);
	             // returnJSON  
	             // ....
	             ///
	})
        .catch((error) => {
	            displayInfo(" Error : " + error, data);
	});

</script>