<div class="alsProx">
        Proximity Threshold = 
        <input type="number" id="proxThreshold" name="prox" 
            min="0" max="255" maxlength="3" value="50" onChange="updateProx()" class="proxInput"> 
        <br>Ambient Light Sensor Value = 
        <output id="alsValue" name="als">?</output>    
    </div>
.alsProx {
  text-align: center;
  background-color: grey;
  color: black;
  border:2px solid black;
  border-radius:8px;
  margin: 20px;
  font-size: 16px;
  font-family: sans-serif;
}
.alsProx input[type=number] {
  text-align: center;
  font-weight: bold;
  border:2px solid black;
  border-radius:8px;
  height: 20px;
  width: 50px;
  font-size: 16px;
  font-family: sans-serif;
}
function updateProx() {
    var proxValue = parseInt(document.getElementById('proxThreshold').value);
    window.nexpaqAPI.DevMod.send("PROX_THRESHOLD", [proxValue]);
}

function dataHandler() {
    var commandType = window.nexpaqAPI.DevMod.last_data.cmdType;
    switch (parseInt(commandType)) {
    case 10:
        document.getElementById('alsValue').value = 
        window.nexpaqAPI.DevMod.last_data.alsData;
        break;
    default:
        toggleButton();
        break;
    }
}
Rerun