function formatField(obj) {
   var n = Number(obj.value);
   if (!isNaN(n)) {
    	var s = n.toFixed(3); 
	obj.value = s
   } else {
      alert("Please only enter numbers");
   }
}


function updateTurns(obj) {
   var n = Number(obj.value);
   if (!isNaN(n)) {
        var s = n.toFixed(0);
        obj.value = s
   } else {
      alert("Please only enter numbers");
   }
}


function convertMM(obj) {
var myUOM = document.getElementById('uom');
	if (myUOM.value == 'Millimeters')
	{
	document.getElementById('thick_mm').innerHTML ='(mm)';
	document.getElementById('section_mm').innerHTML ='(mm)';
	document.getElementById('wh1_mm').innerHTML ='(mm)';
	document.getElementById('wh2_mm').innerHTML ='(mm)';
	document.getElementById('lwh1_mm').innerHTML ='(N)';
	document.getElementById('lwh2_mm').innerHTML ='(N)';
	} else {
        document.getElementById('thick_mm').innerHTML ='(in)';
        document.getElementById('section_mm').innerHTML ='(in)';
        document.getElementById('wh1_mm').innerHTML ='(in)';
        document.getElementById('wh2_mm').innerHTML ='(in)';
        document.getElementById('lwh1_mm').innerHTML ='(lbf)';
        document.getElementById('lwh2_mm').innerHTML ='(lbf)';
	}

	if (document.getElementById('od_mm') && myUOM.value == 'Millimeters')
	{
	document.getElementById('od_mm').innerHTML ='(mm)';
	}

        if (document.getElementById('od_mm') && myUOM.value == 'Inches')
        {
        document.getElementById('od_mm').innerHTML ='(in)';
        }

}


function getTurns(obj) {
var mySpring = document.getElementById('spring_type');
if(mySpring.value == 'Single Overlap' || mySpring.value == 'Single Gap')
        {
	document.getElementById('turns').length = 0;
	document.getElementById('turns').options[1]= new Option('1', 1);
        } else {
	document.getElementById('turns').length = 0;
	document.getElementById('turns').options[1]= new Option('1', 1);
	document.getElementById('turns').options[2]= new Option('2', 2);
	document.getElementById('turns').options[3]= new Option('3', 3);
	document.getElementById('turns').options[4]= new Option('4', 4);
	document.getElementById('turns').options[5]= new Option('5', 5);
	document.getElementById('turns').options[6]= new Option('6', 6);
	document.getElementById('turns').options[7]= new Option('7', 7);
	document.getElementById('turns').options[8]= new Option('8', 8);
	document.getElementById('turns').options[9]= new Option('9', 9);
	document.getElementById('turns').options[10]= new Option('10', 10);
	document.getElementById('turns').options[11]= new Option('11', 11);
	document.getElementById('turns').options[12]= new Option('12', 12);
	document.getElementById('turns').options[13]= new Option('13', 13);
	document.getElementById('turns').options[14]= new Option('14', 14);
	document.getElementById('turns').options[15]= new Option('15', 15);
	}
}

var xmlhttp;

function GetXmlHttpObject()
{
if (window.XMLHttpRequest)
  {
  // code for IE7+, Firefox, Chrome, Opera, Safari
  return new XMLHttpRequest();
  }
if (window.ActiveXObject)
  {
  // code for IE6, IE5
  return new ActiveXObject("Microsoft.XMLHTTP");
  }
return null;
}


function showMaterial(str)
{
xmlhttp=GetXmlHttpObject();
if (xmlhttp==null)
  {
  alert ("Browser does not support HTTP Request");
  return;
  }
var url="get_material.php";
url=url+"?q="+str;
url=url+"&sid="+Math.random();
xmlhttp.onreadystatechange=stateChangedMaterial;
xmlhttp.open("GET",url,true);
xmlhttp.send(null);
}

function stateChangedMaterial()
{
if (xmlhttp.readyState==4)
{
document.getElementById("txtMaterial").innerHTML=xmlhttp.responseText;
}
}


function showSpring(str)
{
xmlhttp=GetXmlHttpObject();
if (xmlhttp==null)
  {
  alert ("Browser does not support HTTP Request");
  return;
  }
var url="get_spring_type.php";
url=url+"?q="+str;
url=url+"&sid="+Math.random();
xmlhttp.onreadystatechange=stateChangedSpring;
xmlhttp.open("GET",url,true);
xmlhttp.send(null);
}

function stateChangedSpring()
{
if (xmlhttp.readyState==4)
{
document.getElementById("txtSpring").innerHTML=xmlhttp.responseText;
}
}




function showDiam(str)
{
xmlhttp=GetXmlHttpObject();
if (xmlhttp==null)
  {
  alert ("Browser does not support HTTP Request");
  return;
  }
var url="get_diam_type.php";
url=url+"?q="+str;
url=url+"&sid="+Math.random();
xmlhttp.onreadystatechange=stateChangedDiam;
xmlhttp.open("GET",url,true);
xmlhttp.send(null);
}

function stateChangedDiam()
{
if (xmlhttp.readyState==4)
{
document.getElementById("txtDiam").innerHTML=xmlhttp.responseText;

var myUOM = document.getElementById('uom');
        if (document.getElementById('od_mm') && myUOM.value == 'Millimeters')
        {
        document.getElementById('od_mm').innerHTML ='(mm)';
        }
}
}

function showTurns(str)
{
xmlhttp=GetXmlHttpObject();
if (xmlhttp==null)
  {
  alert ("Browser does not support HTTP Request");
  return;
  }
var url="waves_per_turn.php";
url=url+"?q="+str;
url=url+"&sid="+Math.random();
xmlhttp.onreadystatechange=stateChangedTurns;
xmlhttp.open("GET",url,true);
xmlhttp.send(null);
}

function stateChangedTurns()
{
if (xmlhttp.readyState==4)
{
document.getElementById("txtTurns").innerHTML=xmlhttp.responseText;
}
}