getElementById() Method JS+BS

Question

how can i take the parameter(number) on a bootstrap input element when i click on the button??

<form>
   <div class="form-group">
    <div class ="col-md-6 input-group">
     <span class="input-group-addon">Larghezza</span>
        <div id="myNumber"> <input type="number" class="form-control" id="focusedInput" placeholder="Inserisci qui..." > </div>
    </div>
  </div>
</form>
 <button type="button" onclick="myFunction()" class="btn btn-default">Calcola</button>

my js code... Then i use the number for some math operation

function myFunction() {
    var x = document.getElementById("myNumber").value;

Answer 1

You are reading value property of div element while it is a property of the input .

Use id of input and it will work.

 function myFunction() { var x = document.getElementById("focusedInput").value; console.log(x); } 

 <form> <div class="form-group"> <div class ="col-md-6 input-group"> <span class="input-group-addon">Larghezza</span> <div id="myNumber"> <input type="number" class="form-control" id="focusedInput" placeholder="Inserisci qui..." > </div> </div> </div> </form> <button type="button" onclick="myFunction()" class="btn btn-default">Calcola</button> 

Answer 2

var x = document.getElementById("focusedInput").value;

您需要引用输入元素，而不是其容器。