function convertMedium(ele,value){
	
	if(ele=="kjkgk"){
		value = (value / 4.1868);
		value = Math.round(value * 1000) / 1000;
		document.getElementById("btulbf").value=value;
	}
	if(ele=="btulbf"){
		value = (value * 4.1868);
		value = Math.round(value * 1000) / 1000;
		document.getElementById("kjkgk").value=value;
	}
}

function popMedium(medium){
	var kjkgk = 0;
	var btulbf = 0;
	
	if(medium=="air")               {kjkgk=1.01;btulbf=0.241;}
	if(medium=="ammonia")           {kjkgk=2.13;btulbf=0.508;}
	if(medium=="argon")             {kjkgk=0.52;btulbf=0.124;}
	if(medium=="benzene")           {kjkgk=1.94;btulbf=0.4634;}
	if(medium=="butane-iso")        {kjkgk=2.08;btulbf=0.4968;}
	if(medium=="butane-n")          {kjkgk=2.10;btulbf=0.502;}
	if(medium=="carbon-dioxide")    {kjkgk=0.86;btulbf=0.205;}
	if(medium=="carbon-monoxide")   {kjkgk=1.04;btulbf=0.248;}
	if(medium=="chlorine")          {kjkgk=0.48;btulbf =0.115;}
	if(medium=="crude-oil")         {kjkgk=2.00;btulbf=0.1935;}
	if(medium=="ethane")            {kjkgk=1.77;btulbf=0.423;}
	if(medium=="ethene")            {kjkgk=1.55;btulbf=0.370;}
	if(medium=="fuel-gas")          {kjkgk=2.30;btulbf=0.549;}
	if(medium=="helium")            {kjkgk=5.20;btulbf=1.242;}
	if(medium=="hydrogen")          {kjkgk=14.40;btulbf=3.439;}
	if(medium=="hydrogen-chloride") {kjkgk=0.81;btulbf=0.1935;}
	if(medium=="methane")           {kjkgk=2.24;btulbf=0.535;}
	if(medium=="natural-gas")       {kjkgk=2.78;btulbf=0.664;}
	if(medium=="nitrogen")          {kjkgk=1.04;btulbf=0.248;}
	if(medium=="oxygen")            {kjkgk=0.92;btulbf=0.220;}
	if(medium=="propane")           {kjkgk=1.67;btulbf=0.399;}
	if(medium=="sulphur-dioxide")   {kjkgk=0.44;btulbf=0.105;}
	if(medium=="water")             {kjkgk=4.20;btulbf=1.00;}
	if(medium=="water-vapour")      {kjkgk=1.90;btulbf=0.454;}

    document.getElementById("kjkgk").value=kjkgk;
    document.getElementById("btulbf").value=btulbf;
}

function convertTemp(measure,ele,value){

	if(measure=="f"){

		var updValue = (value - 32);
			updValue = (updValue / 1.8);
			updValue = Math.round(updValue * 100) / 100;

     if(ele=="start") eleDo="celsius-start-temp";
	 if(ele=="outlet") eleDo="celsius-outlet-temp";

	 document.getElementById(eleDo).value=updValue;
	}
	
	if(measure=="c"){
		
		var updValue = (1.8 * value);
			updValue = (updValue + 32);
			updValue = Math.round(updValue * 100) / 100;

     if(ele=="start") eleDo="fahrenheit-start-temp";
	 if(ele=="outlet") eleDo="fahrenheit-outlet-temp";

	 document.getElementById(eleDo).value=updValue;
	}
	
	var startTemp = document.getElementById("celsius-start-temp").value;
	var outletTemp = document.getElementById("celsius-outlet-temp").value;
	tempChange = (outletTemp - startTemp);
	tempChange = Math.round(tempChange * 100) / 100;
	document.getElementById("temp-change").value=tempChange;

}

function calculate(){
	
	var medium = document.getElementById("kjkgk").value;
	var tempChange = document.getElementById("temp-change").value;
	var massFlowRate = document.getElementById("mass-flow-rate").value;
	
	var kw=(massFlowRate * medium * tempChange);
		kw=(kw / 3600);
		kw= Math.round(kw * 100) / 100;
		
	var btuh=(kw * 3415.179);
		btuh= Math.round(btuh * 100) / 100;

	document.getElementById("rating").innerHTML='<br /><h2>kW: ' + kw + '</h2><h2>BTU/h: ' + btuh + '</h2>';
	
}