var decimalPointDelimiter = "." ;

function isDigit (c){
  return ((c >= "0") && (c <= "9"))
}

function isEmpty(s){
  return ((s == null) || (s.length == 0))
}

function isFloat (s){
  var i;
  
  var seenDecimalPoint = false;
  if (isEmpty(s)) return false;    
  if (s == decimalPointDelimiter) return false;
  for (i = 0; i < s.length; i++){   
    var c = s.charAt(i);
    if ((c == decimalPointDelimiter) && !seenDecimalPoint) 
	  seenDecimalPoint = true;
    else if (!isDigit(c)) return false;
  }

  return true;
}


function calc(errorMsg)
 {   	
 	
   if 	(	isFloat(document.calculator.blt_l.value) &&
  			isFloat(document.calculator.bl_100.value) &&
  			isFloat(document.calculator.dlt_l.value) &&
  			isFloat(document.calculator.blt_100.value) &&
  			isFloat(document.calculator.dlt_100.value) &&
  			isFloat(document.calculator.km_men.value) &&
  			isFloat(document.calculator.km10000.value)	) 
  			{  		
  				doCalc();
  			}
  			else
  			{
  				alert(errorMsg);
  				return false;
  			}	
 	
 }

  function showFoto(src,width,height)
 {

	xposition=70; yposition=40;
		if ((parseInt(navigator.appVersion) >= 4 )){
			xposition = (screen.width - width) / 2;
			yposition = (screen.height - height) / 2;
		}
		args = "width=" + width + ","
			    + "height=" + height + ","
				+ "location=0,"
				+ "menubar=0,"
				+ "resizable=0,"
				+ "scrollbars=0,"
				+ "statusbar=0,"
				+ "titlebar=0,"
				+ "toolbar=0,"
				+ "hotkeys=0,"
				+ "screenx=" + xposition + ","  //NN Only
				+ "screeny=" + yposition + ","  //NN Only
				+ "left=" + xposition + ","     //IE Only
				+ "top=" + yposition;           //IE Only
   window.open('?q=showImage&id='+src,'_blank',args);
		
 }

 function doCalc()
  {    	
 		document.calculator.blt_100.value 	= Math.round(parseFloat(document.calculator.blt_l.value)*parseFloat(document.calculator.bl_100.value)*100)/100;
		document.calculator.dl_100.value  =	 Math.round(parseFloat(document.calculator.bl_100.value)*1.2*10)/10;
		document.calculator.dlt_100.value = 	Math.round(parseFloat(document.calculator.dlt_l.value)*parseFloat(document.calculator.dl_100.value)*100)/100;
		document.calculator.km10000.value = Math.round((parseFloat(document.calculator.blt_100.value)-parseFloat(document.calculator.dlt_100.value))*100);
		document.calculator.lt_men.value  = Math.round(parseFloat(document.calculator.km_men.value)*parseFloat(document.calculator.km10000.value)/10000*100)/100;
		document.calculator.lt_mt.value   = Math.round( parseFloat(document.calculator.km_men.value)*12*parseFloat(document.calculator.km10000.value/10000)*100)/100	;		
  }