Converting from Lo22/19 to EPSG:4326

HTML

<script src="//cdnjs.cloudflare.com/ajax/libs/proj4js/2.2.1/proj4.js"></script>
X :
<input type="text" id="X"value="55435.89">
<br>Y :
<input type="text" id="Y"value="-498157.28">
<br>
<input type="button" id="convertButton" value="Convert" onclick="convertCoords()">
<br>
<div id="con_output">

CSS

#con_output {
    width:100px;
    height:100px;
}

JavaScript

var GCS84 = "+proj=longlat +ellps=WGS84 +datum=WGS84 +no_defs";
var Lo22 = "+proj=tmerc +lat_0=-22 +lon_0=17 +k=1 +x_0=0 +y_0=0 +a=6377397.155 +rf=299.1528128 +towgs84=616,97,-251,0,0,0,0 +units=m +no_defs"

    function convertCoords() {
        var x = Number(document.getElementById("X").value);
        var y = Number(document.getElementById("Y").value);
        var transformed = proj4(Lo22, GCS84, [x, y]);

        var value = String(transformed[1]) + "S ," + String(transformed[0])+"E";
        
        document.getElementById("con_output").innerHTML = value;
    }