function Exampleinput(){

document.calc.Cadisplay.write ("Hello");}

function ionbalance(Samp,Ca,Mg,Na,K,HCO3,Alkunit,Cl,SO4,NO3){ 

if (Ca.length==0) {alert ( "You must enter a number in 'Calcium'"); return;}
if (Mg.length==0) {alert ( "You must enter a number in 'Magnesium'"); return;}
if (Na.length==0) {alert ( "You must enter a number in 'Sodium'"); return;}
if (K.length==0) {alert ( "You must enter a number in 'Potassium'"); return;}
if (HCO3.length==0) {alert ( "You must enter a number in 'Alkalinity'"); return;}
if (Cl.length==0) {alert ( "You must enter a number in 'Chloride'"); return;}
if (SO4.length==0) {alert ( "You must enter a number in 'Sulphate'"); return;}
if (NO3.length==0) {alert ( "You must enter a number in 'Nitrate'"); return;}

if (isNaN(Ca)) {alert ( "You must enter a number in 'Calcium'"); return;}
if (isNaN(Mg)) {alert ( "You must enter a number in 'Magnesium'"); return;}
if (isNaN(Na)) {alert ( "You must enter a number in 'Sodium'"); return;}
if (isNaN(K)) {alert ( "You must enter a number in 'Potassium'"); return;}
if (isNaN(HCO3)) {alert ( "You must enter a number in 'Alkalinity'"); return;}
if (isNaN(Cl)) {alert ( "You must enter a number in 'Chloride'"); return;}
if (isNaN(SO4)) {alert ( "You must enter a number in 'Sulphate'"); return;}
if (isNaN(NO3)) {alert ( "You must enter a number in 'Nitrate'"); return;}

if (Ca<0) {alert ("Please enter a value for Calcium of 0 or more"); return;}
if (Mg<0) {alert ("Please enter a value for Magnesium of 0 or more"); return;}
if (Na<0) {alert ("Please enter a value for Sodium of 0 or more"); return;}
if (K<0) {alert ("Please enter a value for Potassium of 0 or more"); return;}
if (HCO3<0) {alert ("Please enter a value for Alkalinity of 0 or more"); return;}
if (Cl<0) {alert ("Please enter a value for Chloride of 0 or more"); return;}
if (SO4<0) {alert ("Please enter a value for Sulphate of 0 or more"); return;}
if (NO3<0) {alert ("Please enter a value for Nitrate of 0 or more"); return;}


var Caeq=Ca/20;
var Mgeq=Mg/12.15;
var Naeq=Na/23;
var Keq=K/39.1;
var HCO3eq=HCO3/61;


if (Alkunit==1) HCO3eq*=1.22;
var Cleq=Cl/35.5;
var SO4eq=SO4/48;
var NO3eq=NO3/62;

var cattoteq=(Caeq+Mgeq+Naeq+Keq);

var antoteq=(HCO3eq+Cleq+SO4eq+NO3eq);

var ionratio=cattoteq/antoteq;


var description="";


if ((ionratio)>=0.95&&(ionratio)<=1.05) description="The ion balance is good.";
if ((ionratio)>=0.90&&(ionratio)<0.95) description="The ion balance is fair.";
if ((ionratio)<0.90) description="The ion balance is poor.";
if ((ionratio)>1.05&&(ionratio)<=1.10) description="The ion balance is fair.";
if ((ionratio)>1.10) description="The ion balance is poor.";

var ir100=ionratio*100;

var ir100round=Math.round(ir100);

ionratio=ir100round/100;

var answer="";
 
answer=(description)+" The ratio of cations to anions is "+(ionratio)+".";

var Caeq10=Caeq*10;
var Caeq10round=Math.round(Caeq10);
Caeq=Caeq10round/10;

var Mgeq10=Mgeq*10;
var Mgeq10round=Math.round(Mgeq10);
Mgeq=Mgeq10round/10;

var Naeq10=Naeq*10;
var Naeq10round=Math.round(Naeq10);
Naeq=Naeq10round/10;

var Keq10=Keq*10;
var Keq10round=Math.round(Keq10);
Keq=Keq10round/10;

var HCO3eq10=HCO3eq*10;
var HCO3eq10round=Math.round(HCO3eq10);
HCO3eq=HCO3eq10round/10;

var Cleq10=Cleq*10;
var Cleq10round=Math.round(Cleq10);
Cleq=Cleq10round/10;

var SO4eq10=SO4eq*10;
var SO4eq10round=Math.round(SO4eq10);
SO4eq=SO4eq10round/10;

var NO3eq10=NO3eq*10;
var NO3eq10round=Math.round(NO3eq10);
NO3eq=NO3eq10round/10;

document.calc.answers.value=(answer);

var div=(cattoteq);
if ((cattoteq)<(antoteq)) div=(antoteq);
 
var Cabarlength=(Caeq)*600/(div);
var Cabar=new Image();
Cabar.src="ib/Cabar.gif";
document.calc.Cadisplay.src=Cabar.src;
document.calc.Cadisplay.width=Cabarlength;

var Mgbarlength=(Mgeq)*600/(div);
var Mgbar=new Image();
Mgbar.src="ib/Mgbar.gif";
document.calc.Mgdisplay.src=Mgbar.src;
document.calc.Mgdisplay.width=Mgbarlength;

var Nabarlength=(Naeq)*600/(div);
var Nabar=new Image();
Nabar.src="ib/Nabar.gif";
document.calc.Nadisplay.src=Nabar.src;
document.calc.Nadisplay.width=Nabarlength;

var Kbarlength=(Keq)*600/(div);
var Kbar=new Image();
Kbar.src="ib/Kbar.gif";
document.calc.Kdisplay.src=Kbar.src;
document.calc.Kdisplay.width=Kbarlength;

var HCO3barlength=(HCO3eq)*600/(div);
var HCO3bar=new Image();
HCO3bar.src="ib/Alkbar.gif";
document.calc.HCO3display.src=HCO3bar.src;
document.calc.HCO3display.width=HCO3barlength;

var Clbarlength=(Cleq)*600/(div);
var Clbar=new Image();
Clbar.src="ib/Clbar.gif";
document.calc.Cldisplay.src=Clbar.src;
document.calc.Cldisplay.width=Clbarlength;

var SO4barlength=(SO4eq)*600/(div);
var SO4bar=new Image();
SO4bar.src="ib/Sulbar.gif";
document.calc.SO4display.src=SO4bar.src;
document.calc.SO4display.width=SO4barlength;

var NO3barlength=(NO3eq)*600/(div);
var NO3bar=new Image();
NO3bar.src="ib/Nitbar.gif";
document.calc.NO3display.src=NO3bar.src;
document.calc.NO3display.width=NO3barlength;

var Alkdisp="HCO3";
if (Alkunit==1) Alkdisp="CaCO3"; 

var record=("Sample ID="+(Samp)+": Ca="+(Ca)+"mg/l: Mg="+(Mg)+"mg/l: Na="+(Na)+"mg/l: K="+(K)+"mg/l: Alk="+(HCO3)+"mg/l as "+(Alkdisp)+": Cl="+(Cl)+"mg/l: SO4="+(SO4)+"mg/l: NO3="+(NO3)+"mg/l:");

cumanswer+=(record)+"<BR>"+(answer)+"<BR><BR>";
}

function showresults(){

answin =window.open("","answin","width=960,height=450,menubar=yes,status=no,resizeable=no,scrollbars=yes");
answin.document.write (cumanswer);
answin.document.close();
answin.moveTo(0,0);}

function gwexample(){

document.calc.Samp.value="Groundwater example";
document.calc.Ca.value=51.4;
document.calc.Mg.value=23.5;
document.calc.Na.value=22.8;
document.calc.K.value=15.0;
document.calc.HCO3.value=270.5;
document.calc.Cl.value=12.3;
document.calc.SO4.value=24.2;
document.calc.NO3.value=38;}

function swexample(){

document.calc.Samp.value="Seawater example";
document.calc.Ca.value=418;
document.calc.Mg.value=1330;
document.calc.Na.value=11035;
document.calc.K.value=397;
document.calc.HCO3.value=146;
document.calc.Cl.value=19841;
document.calc.SO4.value=2769;
document.calc.NO3.value=0;}