function calculateCalorieCutting(btn){
	var elWeight = YAHOO.util.Dom.get("lbsToLose");
	var elTime = YAHOO.util.Dom.get("weeksToLose");
	var o = YAHOO.util.Dom.get("caloriesToCut");
	if(!btn.id){
		if(isNaN(parseFloat(elWeight.value))){
			resetCalorieCutting(o);
			return;
		};
		if(isNaN(parseFloat(elTime.value))){
			resetCalorieCutting(o);
			return;
		};
	};
	if(isNaN(parseFloat(elWeight.value)) || elWeight.value<=0){
		resetCalorieCutting(o);
		return warnInvalid(elWeight,"Please enter a positive number for the pounds.");
	};
	if(isNaN(parseFloat(elTime.value)) || elTime.value<=0){
		resetCalorieCutting(o);
		return warnInvalid(elTime,"Please enter a positive number for the weeks.");
	};
	var CC = elWeight.value * 3500 / elTime.value / 7;
	if(isNaN(CC)){
		resetCalorieCutting(o);
		if(btn.id){
			return warnInvalid("","Either the number of pounds entered or the number of weeks entered was invalid.");
		};
	}else{
		o.innerHTML = Math.round(CC);
	};
};

function resetCalorieCutting(obj){
	obj.innerHTML = "&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;";	
};

YAHOO.util.Event.addListener(YAHOO.util.Dom.get("lbsToLose"),"keyup",calculateCalorieCutting);
YAHOO.util.Event.addListener(YAHOO.util.Dom.get("weeksToLose"),"keyup",calculateCalorieCutting);