function Calculate(what){
		if(document.CALC.touchedlast.value==""){
			err("wrong")
			return
		}
		if(what=="temp"){
			if(document.CALC.touchedlast.value=="celsius"){
				if(isNaN(document.CALC.celsius.value)){
					err("temp");
				}else{
					CtoF(document.CALC.celsius.value);
				}
			}else if(document.CALC.touchedlast.value=="fahrenheit"){
				if(isNaN(document.CALC.fahrenheit.value)){
					err("temp");
				}else{
					FtoC(document.CALC.fahrenheit.value);
				}
			}else{
				err("wrong");
				return
			}
		}else{
			if(document.CALC.touchedlast.value=="mm"){
				if(isNaN(document.CALC.mm.value)){
					err("length");
				}else{
					MtoI(document.CALC.mm.value);
				}
			}else if(document.CALC.touchedlast.value=="inches"){
				if(isNaN(document.CALC.inches.value)){
					err("length");
				}else{			
					ItoM(document.CALC.inches.value);
				}
			}else{
				err("wrong");
				return
			}
		}
	}
	
	function err(type){
		if(type=="temp"){
			alert("The value you are trying to calculate is not a number.  \nPlease try again.");
			document.CALC.celsius.value="";
			document.CALC.fahrenheit.value="";
			document.CALC.touchedlast.value="";
			return
		}else if(type=="length"){
			alert("The value you are trying to calculate is not a number.  \nPlease try again.");
			document.CALC.mm.value="";
			document.CALC.inches.value="";
			document.CALC.touchedlast.value="";
			return
		}else{
			alert("The value you are trying to calculate is invalid.  \nPlease try again.");
		}
	}
	
	function frmtNumber(expression,NumDigitsAfterDecimal){
		var strNum = new String(expression)
		var re = ".";
		var intDec = strNum.indexOf(re)
		if(intDec>0){
			intDec = (parseInt(intDec)+(NumDigitsAfterDecimal+1))
			strNum = strNum.substr(0,intDec)
			return strNum
		}else{
			return strNum
		}
	}
	function WhosLast(fld){
		document.CALC.touchedlast.value=fld;
	}
	function CtoF(tmp){
		var intTemp=tmp;
		intTemp=(intTemp*9);
		intTemp=(intTemp/5);
		intTemp=(intTemp+32);
		document.CALC.fahrenheit.value=frmtNumber(intTemp,1);
	}
	
	function FtoC(tmp){
		var intTemp=tmp;
		intTemp=(intTemp-32);
		intTemp=(intTemp/9);
		intTemp=(intTemp*5);
		document.CALC.celsius.value=frmtNumber(intTemp,1);
	}
	
	function ItoM(len){
		var intLength=len
		if(intLength.length>0){
			intLength=(intLength*25.38);
			document.CALC.mm.value=frmtNumber(intLength,2);
		}
	}
	
	function MtoI(len){
		var intLength=len
		if(intLength.length>0){
			intLength=(intLength/25.38);
			document.CALC.inches.value=frmtNumber(intLength,2);
		}
	}