<div class="balance-btc-html">0.00001912</div>

<input class="form-control text-center" id="amount" value="0.00000001" type="text">

[HTML] pobierz, plaintext 
<form action="" method="post">
	<input type="number" name="number"step="10"/>
	<input type="submit">
</form>
 <div id="insert_here"></div>
[HTML] pobierz, plaintext 

<script>

var insert_here = document.getElementById('insert_here');

document.addEventListener('DOMContentLoaded',function() {
    document.querySelector('input[type="number"]').onchange=changeEventHandler;
},false);

function changeEventHandler(event) {
    // You can use “this” to refer to the selected element.
    if(!event.target.value){
        insert_here.innerHTML = ('Please Select One');
        
    }else{
    
        insert_here.innerHTML = ('You like ' + event.target.value + ' ice cream.');
    
      if(event.target.value==100){
        document.querySelector('input[type="number"]').setAttribute('step',100);
      }
    
    }
}
</script>