function check(ad)
{
	var ch=ad.value;
	if(isNaN(ch))
	{
		var df=ch.substring(0,(ch.length-1))
		ad.value=df;
	}	
}

function calc()
{
	var wt = document.bmi.wg.value;
	var ht = document.bmi.ht.value;
	
	var op = document.bmi.opt1.value;
	
	//SI value
	var h = ht/100;
	var si = Math.round((wt/(h*h))*100)/100;
	document.bmi.si.value = si;
	
	//US value
	var lb = wt*2.2;
	var ic = ht*0.39;
	var us = Math.round((703*(lb/(ic * ic)))*100)/100;
	document.bmi.us.value = us;
	
	//UK value
	var uk = Math.round((6.35*si)*100)/100;
	document.bmi.uk.value = uk;
	
	//If value is not given for weight
	if(wt=="")
	{
		alert("Enter the value for weight");
	}

	//If weight is less than 10
	else if(wt<=10)
	{
		document.bmi.si.value = 0;
		document.bmi.us.value = 0;
		document.bmi.uk.value = 0;
		alert("Weight should be greater than 10kgs");
	}
	
	//If weight is pounds and less than 22lbs
	else if(op=="pounds" && wt<=22)
	{
		document.bmi.si.value = 0;
		document.bmi.us.value = 0;
		document.bmi.uk.value = 0;
		alert("Weight should be greater than 22lbs");
	}
	
	//If given height is less than 33cms
	else if(ht<33)
	{
		document.bmi.si.value = 0;
		document.bmi.us.value = 0;
		document.bmi.uk.value = 0;
		alert("Height should be taller than 33cms");
	}
	else if(op=="pounds")
	{
		document.bmi.si.value=Math.round((si/2.2)*100)/100;
		document.bmi.us.value=Math.round((us/2.2)*100)/100;
		document.bmi.uk.value=Math.round((uk/2.2)*100)/100;
		
	}
	var d = "Your category is ";
	var c = document.bmi.si.value;
	if(c<15)
	{
		document.bmi.desc.value= d + "Starvation";
	}
	else if(c>15 && c<=18.5)
	{
		document.bmi.desc.value= d + "Underweight";
	}
	else if(c>18.5 && c<=25)
	{	
		document.bmi.desc.value= d + "Normal";	
	}
	else if(c>25 && c<=30)
	{
		document.bmi.desc.value=d + "Overweight";
	}
	else if(c>30)
	{
		document.bmi.desc.value=d + "Obese";
	}
}


function conv(aa)//Height conversion
{
	var ft=0, inc=0, ht=0;
	if(aa==1 || aa==2)
	{
		ft = document.bmi.opt2.value;
		inc = document.bmi.opt3.value;
		var ss = ft*12;
		var tot = ss+parseInt(inc);
       	var val= tot*2.54;
		document.bmi.ht.value = Math.round(val);
	}

	else{
		ht = document.bmi.ht.value;
		if(ht!="")
		{
			var cm=Math.round(ht/2.54);
			var div=parseInt(cm/12);
			var md=cm%12;
			document.bmi.opt2.value=div;
			document.bmi.opt3.value=md;
		}
         }

}


function unit()  //Weight conversion
{
	var pp = document.bmi.opt1.value;
	var ww = document.bmi.wg.value;
	
	//Kilogram to pounds
	if(pp=="pounds")	
	{
		document.bmi.wg.value = Math.round((ww*2.2)*100)/100;
	}

	//Pounds to kilograms
	else
	{
		document.bmi.wg.value=Math.round(ww/2.2);
	}
}