$(document).ready(function(){
  
  var getValue1 = function(val, unit) {
    var out = $(val).val();
    var order = 5;
    
    switch ($(unit).val())
    {
      case '0':
        order = 12;
        break;
      
      case '1':
        order = 9;
        break;

      case '2':
        order = 6;
        break;
    }
    
    out = out/Math.pow(10,order);
    
    return out;
  }
  
 $("#calculate").click(function(event){
 
  var c1 = getValue1("#c1", "#c1unit");
  var c2 = getValue1("#c2", "#c2unit");
  var v1 = $("#Vin").val();
  var v2 = 0;
  
  v2 = v1 * (c1 / (c1 + c2));
  
  $("#result").html(v2);
 });
});