function ValueClear(Data) {
	document.calc_disk.ncamera.value = Data;
	document.calc_disk.imgsize.value = Data;
	document.calc_disk.fps.value = Data;
	document.calc_disk.recday.value = Data;
	document.calc_disk.rectime.value = Data;
	document.getElementById('diskspace_value').innerHTML = Data;
	}

function formatDecimal(val) {
	val = Math.round(val*100)/100;
	var dval = "" + val;
		if ( (dval.indexOf(".") != -1) && (dval.length > dval.indexOf(".") + 3))
		dval = dval.substring(0, dval.indexOf(".") + 3);
	return dval; 
}

function BytePerSec() {
	var BytePS = 0;
		 BytePS = document.calc_disk.imgsize.value * document.calc_disk.fps.value *  document.calc_disk.ncamera.value;
		  return BytePS;
}

function DataCapacity() {
	var Day_Data = BytePerSec();
	Day_Data = Day_Data * (60 * 60 * 24);
	
	var DayRecord = document.calc_disk.recday.value * (document.calc_disk.rectime.value / 24);
	var DataCap = Day_Data * DayRecord
	DataCap = DataCap / (1024 * 1024);
	
	//document.calc_disk.diskspace.value = formatDecimal (DataCap );    // / (1024 * 1024)
	document.getElementById('diskspace_value').innerHTML = formatDecimal (DataCap );
	//document.getElementById('diskspace_value').insertAdjacentHTML("AfterBegin", formatDecimal(DataCap));
	}
	
function calc() {
	BytePerSec();
	DataCapacity();
}