function textOnChange(div){
	 var obj=document.getElementById(div);
	 
	 
	 if (!isNaN(obj.value)){
	 if (obj.value>0)var res=obj.getAttribute("prezzo1");
	 if (obj.value>5)var res=obj.getAttribute("prezzo2");
	 if (obj.value>20)var res=obj.getAttribute("prezzo3");
	 
	document.getElementById("res_"+ div).innerText=obj.value + " x "+  res + "=" + ((obj.value*res.replace(",",".")).toFixed(2)).replace(".",","); ;
		}
	
	
	
	}