<p><center><b>Расчет давления</b></center></p>
<p>
<table border=1 cellpadding=5>
<tr>
	<td>Превышение аэродрома:</td>
	<td>
	<input type='text' id='prevish_m' value='0' size='7' onChange='Calculate(document.getElementById("prevish_m").value, "prevish_m");'> метров<br>
	<input type='text' id='prevish_f' value='0' size='7' onChange='Calculate(document.getElementById("prevish_f").value, "prevish_f");'> футов
	</td>
</tr>
</table>
<br>
<table border=1 cellpadding=5>
<tr>
	<td><center>QNH</center></td>
	<td><center>QFE</center></td>
</tr>
<tr>
	<td>
	<input type='text' id='qnh_inch' value='0' size='10' onChange='Calculate(document.getElementById("qnh_inch").value, "qnh_inch");'> д.рт.ст.<br>
	<input type='text' id='qnh_mm' value='0' size='10' onChange='Calculate(document.getElementById("qnh_mm").value, "qnh_mm");'> мм.рт.ст.<br>
	<input type='text' id='qnh_bar' value='0' size='10' onChange='Calculate(document.getElementById("qnh_bar").value, "qnh_bar");'> мбар
	</td>
	
	<td>
	<input type='text' id='qfe_inch' value='0' size='10' onChange='Calculate(document.getElementById("qfe_inch").value, "qfe_inch");'> д.рт.ст.<br>
	<input type='text' id='qfe_mm' value='0' size='10' onChange='Calculate(document.getElementById("qfe_mm").value, "qfe_mm");'> мм.рт.ст.<br>
	<input type='text' id='qfe_bar' value='0' size='10' onChange='Calculate(document.getElementById("qfe_bar").value, "qfe_bar");'> мбар
	</td>
</tr>
</table>
</p>

<script language='JavaScript'>

Calculate(29.92, 'qnh_inch');

function Calculate($value, $value_name){
	var $qnh_inch, $qnh_mm, $qnh_bar, $qfe_inch, $qfe_mm, $qfe_bar, $prevish_m, $prevish_f;
	switch($value_name){
		case 'prevish_m':
			$prevish_m = $value;
			$prevish_f = $prevish_m/0.3048;
			$qnh_inch = document.getElementById('qnh_inch').value;
			$qnh_mm = document.getElementById('qnh_mm').value;
			$qnh_bar = document.getElementById('qnh_bar').value;
			$qfe_inch = $qnh_inch - $prevish_m*0.00328144;
			$qfe_mm = 25.4*$qfe_inch;
			$qfe_bar = 33.86*$qfe_inch;
			break;
		case 'prevish_f':
			$prevish_f = $value;
			$prevish_m = $prevish_f*0.3048;
			$qnh_inch = document.getElementById('qnh_inch').value;
			$qnh_mm = document.getElementById('qnh_mm').value;
			$qnh_bar = document.getElementById('qnh_bar').value;
			$qfe_inch = $qnh_inch - $prevish_m*0.00328144;
			$qfe_mm = 25.4*$qfe_inch;
			$qfe_bar = 33.86*$qfe_inch;
			break;
		// ------------------------------------------------	
		case 'qnh_inch': 
			$qnh_inch = $value;
			$qnh_mm = 25.4*$qnh_inch;
			$qnh_bar = 33.86*$qnh_inch;
			$prevish_m = document.getElementById('prevish_m').value;
			$prevish_f = document.getElementById('prevish_f').value;
			$qfe_inch = $qnh_inch - $prevish_m*0.00328144;
			$qfe_mm = 25.4*$qfe_inch;
			$qfe_bar = 33.86*$qfe_inch;
			break;
		case 'qnh_mm': 
			$qnh_mm = $value;
			$qnh_inch = $qnh_mm*0.039368;
			$qnh_bar = 33.86*$qnh_inch;
			$prevish_m = document.getElementById('prevish_m').value;
			$prevish_f = document.getElementById('prevish_f').value;
			$qfe_inch = $qnh_inch - $prevish_m*0.00328144;
			$qfe_mm = 25.4*$qfe_inch;
			$qfe_bar = 33.86*$qfe_inch;
			break;
		case 'qnh_bar': 
			$qnh_bar = $value;
			$qnh_inch = $qnh_bar*0.0295331;
			$qnh_mm = 25.4*$qnh_inch;
			$prevish_m = document.getElementById('prevish_m').value;
			$prevish_f = document.getElementById('prevish_f').value;
			$qfe_inch = $qnh_inch - $prevish_m*0.00328144;
			$qfe_mm = 25.4*$qfe_inch;
			$qfe_bar = 33.86*$qfe_inch;
			break;
		// ------------------------------------------------
		case 'qfe_inch': 
			$qfe_inch = $value;
			$qfe_mm = 25.4*$qfe_inch;
			$qfe_bar = 33.86*$qfe_inch;
			$prevish_m = document.getElementById('prevish_m').value;
			$prevish_f = document.getElementById('prevish_f').value;
			$qnh_inch = $qfe_inch + $prevish_m*0.00328144;
			$qnh_mm = 25.4*$qnh_inch;
			$qnh_bar = 33.86*$qnh_inch;
			break;
		case 'qfe_mm': 
			$qfe_mm = $value;
			$qfe_inch = $qfe_mm*0.039368;
			$qfe_bar = 33.86*$qfe_inch;
			$prevish_m = document.getElementById('prevish_m').value;
			$prevish_f = document.getElementById('prevish_f').value;
			$qnh_inch = $qfe_inch + $prevish_m*0.00328144;
			$qnh_mm = 25.4*$qnh_inch;
			$qnh_bar = 33.86*$qnh_inch;
			break;
		case 'qfe_bar': 
			$qfe_bar = $value;
			$qfe_inch = $qfe_bar*0.0295331;
			$qfe_mm = 25.4*$qfe_inch;
			$prevish_m = document.getElementById('prevish_m').value;
			$prevish_f = document.getElementById('prevish_f').value;
			$qnh_inch = $qfe_inch + $prevish_m*0.00328144;
			$qnh_mm = 25.4*$qnh_inch;
			$qnh_bar = 33.86*$qnh_inch;
			break;	
		
	}
	document.getElementById('prevish_m').value = (Math.round($prevish_m*100))/100;
	document.getElementById('prevish_f').value = (Math.round($prevish_f*100))/100;
	
	document.getElementById('qnh_inch').value = (Math.round($qnh_inch*100))/100;
	document.getElementById('qnh_mm').value = (Math.round($qnh_mm*100))/100;
	document.getElementById('qnh_bar').value = (Math.round($qnh_bar*100))/100;
	
	document.getElementById('qfe_inch').value = (Math.round($qfe_inch*100))/100;
	document.getElementById('qfe_mm').value = (Math.round($qfe_mm*100))/100;
	document.getElementById('qfe_bar').value = (Math.round($qfe_bar*100))/100;
	
}
</script>