Why echo function print data in console? - php

Question

I'm creating page in PHP but when I use AJAX to send data, echo function start to printing data in console instead in DOM elements.
I want to add Quagga barcode reader to my page. Quagga is write in JS but my page is in php. So I have to use Ajax to send barcode result to my php code. And there is a problem. After sending data (POST) and using echo to display that on the screen, every data that echo should display are showing up in console. Not only data I send but whole page html code too. Even header('Location: ') doesn't work correctly. Because I'm sending readed code to barcodereaded.php where I put POST data inside SESSION var, and I try to echo that on the screen in different file barcoderesult.php but everytime data is printed in console log in barcode.php (which code is below). On every other subpage php echo and header functions works fine, only this one case causing troubles.
<div id="scanner-container"></div>
<input type="button" id="btn" value="Start/Stop" />
<script src="js/quagga.min.js"></script>
<script>
var _scannerIsRunning = false;
function startScanner() {
var barcode = {};
Quagga.init({
inputStream: {
name: "Live",
type: "LiveStream",
numOfWorkers: navigator.hardwareConcurrency,
target: document.querySelector('#scanner-container'),
constraints: {
size: 1920,
width: 200,
height: 480,
facingMode: "environment"
},
},
config: {
frequency: 5,
},
locator: {
patchSize: "x-large",
},
decoder: {
readers: [
"code_128_reader",
"ean_reader",
"ean_8_reader",
"code_39_reader",
"code_39_vin_reader",
"codabar_reader",
"upc_reader",
"upc_e_reader",
"i2of5_reader"
],
debug: {
showCanvas: true,
showPatches: true,
showFoundPatches: true,
showSkeleton: true,
showLabels: true,
showPatchLabels: true,
showRemainingPatchLabels: true,
boxFromPatches: {
showTransformed: true,
showTransformedBox: true,
showBB: true
}
}
},
}, function (err) {
if (err) {
console.log(err);
return
}
console.log("Initialization finished. Ready to start");
Quagga.start();
// Set flag to is running
_scannerIsRunning = true;
});
Quagga.onProcessed(function (result) {
var drawingCtx = Quagga.canvas.ctx.overlay,
drawingCanvas = Quagga.canvas.dom.overlay;
if (result) {
if (result.boxes) {
drawingCtx.clearRect(0, 0, parseInt(drawingCanvas.getAttribute("width")), parseInt(drawingCanvas.getAttribute("height")));
result.boxes.filter(function (box) {
return box !== result.box;
}).forEach(function (box) {
Quagga.ImageDebug.drawPath(box, { x: 0, y: 1 }, drawingCtx, { color: "green", lineWidth: 2 });
});
}
if (result.box) {
Quagga.ImageDebug.drawPath(result.box, { x: 0, y: 1 }, drawingCtx, { color: "#00F", lineWidth: 2 });
}
if (result.codeResult && result.codeResult.code) {
Quagga.ImageDebug.drawPath(result.line, { x: 'x', y: 'y' }, drawingCtx, { color: 'red', lineWidth: 3 });
}
}
});
Quagga.onDetected(function (result) {
Quagga.stop();
barcode.code = result.codeResult.code;
$.ajax({
url: "barcodereaded.php",
method: "POST",
data: barcode,
success: function(res){
console.log(res);
}
});
});
}
// Start/stop scanner
document.getElementById("btn").addEventListener("click", function () {
if (_scannerIsRunning) {
Quagga.stop();
_scannerIsRunning = false;
} else {
startScanner();
}
}, false);
</script>
I just want to send readed barcode to other file to convert it into data I want to add to database (quantity of elements on the pallet, production date, etc.)

Answer 1

Look at this part of your code :
$.ajax({
url: "barcodereaded.php",
method: "POST",
data: barcode,
success: function(res){
console.log(res);
}
});
The success method tells what to do with the result of your ajax code.
And here you specifically tell to log the response (res) to the console.
Instead you can use the content of res to append it to your dom via your preferred Javascript solution (vanilla, jQuery,...).
With jQuery you could (if the result from your php code is some text):
$('#my-return-container').text(res)