title: How i can use my back camera of my phone in the browser with QUAGGA JS
body: <p>i want to use Quagga js in my webapp to scan a barcodes...
  The problem is that i want use the mobile's back camera, in the documentation say's that quagga use a parameter called &quot;facingMode&quot;.
  If you set facingMode = &quot;enviroment&quot; that use the webcam if you stay in a PC or the back camera if you stay in a Phone .
  And if you set facingMode = &quot;user&quot; that use the mobile's front camera.
  Well, i set user and enviroment  for test and there is no difference, it stays the same, on the cell phone continues to use the front camera, i try to use the back camera but nothing.
  I leave my code at there</p>
  <pre><code>function startScanner() {
              Quagga.init({
                  inputStream: {
                      name: &quot;Live&quot;,
                      type: &quot;LiveStream&quot;,
                      target: document.querySelector('#scanner-container'),
                      constraints: {
                          width: 600,
                          height: 450,
                          facingMode: &quot;enviroment&quot; //or user for front camera
                      },
                  },
                  decoder: {
                      readers: [
                          &quot;code_128_reader&quot;,
                          &quot;ean_reader&quot;,
                          &quot;ean_8_reader&quot;,
                          &quot;code_39_reader&quot;,
                          &quot;code_39_vin_reader&quot;,
                          &quot;codabar_reader&quot;,
                          &quot;upc_reader&quot;,
                          &quot;upc_e_reader&quot;,
                          &quot;i2of5_reader&quot;
                      ],
                      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(&quot;Initialization finished. Ready to start&quot;);
                  console.log(navigator.mediaDevices.enumerateDevices());
                  Quagga.start();
  
                  // Set flag to is running
                  _scannerIsRunning = true;
              });
  </code></pre>
  <p>i tried in Android Phone</p>