function calc (lg,elem1,elem2,elemsum,disc){
	var e1 = document.getElementById(elem1);
	var e2 = document.getElementById(elem2);
	var sum = document.getElementById(elemsum);
	if(disc>0)
      num = (e1.value * e2.value)-((e1.value * e2.value)*disc/100);
    else
      num = e1.value * e2.value;
    n=num.toFixed(2);
    if(lg==1)
     n=n.replace(".",",");
    
     sum.innerHTML=n;

       
}


function setClass( hEl, sClass ){
    hEl.className = sClass
}

function numbersonly(myfield, e, dec){
	var key;
	var keychar;
	
	if (window.event)
	   key = window.event.keyCode;
	else if (e)
	   key = e.which;
	else
	   return true;
	keychar = String.fromCharCode(key);
	
	if ((key==null) || (key==0) || (key==8) || 
		(key==9) || (key==13) || (key==27) )
	   return true;
	
	else if ((("0123456789").indexOf(keychar) > -1))
	   return true;
	
	else if (dec && (keychar == "."))
	   {
	   myfield.form.elements[dec].focus();
	   return false;
	   }
	else
	   return false;
}