// reading a variable in the parsed string
function getParm(string,parm) {
	var startPos= string.indexOf(parm+"=");
	if (startPos> -1) {
		startPos= startPos+parm.length+1;
		var endPos= string.indexOf("&",startPos);
		if (endPos== -1) endPos= string.length;
		return unescape(string.substring(startPos,endPos));
	}
	return '';
}

// make fraction to comma number
function makeComma(x) {
	vz = ""
	if(x.indexOf("\-") == 0) vz = "-"
	x = x.replace(/\+/, "")
	x = x.replace(/\-/, "")
	if(x.search(/\//) > 0) x = eval(x.replace(/ /, "+"))
	x = eval(vz + x + "")
	return (x)
}

// calculate the Exposure Value
function calcEV (a, s, iso) {
	a = a.replace(/,/, ".") - 0.0
	if(s.search(/\//) > 0) s = eval(s)
	else s = s.replace(/,/, ".") - 0.0
	// EV  =  log2(aperture^2 * (1/shutter speed))
	// Note:  log2(x) = ln(x)/ln(2) = lg(x)/lg(2)  !!
	x  = Math.pow(a,2) * (1/s)
	ev = Math.log(x) / Math.log(2)			// EV @ ISO 100
	// SV  =  log2(0.32 * iso)
	sv = Math.log(0.32 * iso) / Math.log(2)		// speed value
	// EV  =  EV - SV - 5
	ev -= sv - 5
	return ev
}

// compare function for sorting
function sort_result(a, b, reverse) {
	if(reverse<0)
	     return ((a < b) ?  1 : ((a > b) ? -1 : 0))
	else return ((a < b) ? -1 : ((a > b) ?  1 : 0))
}