window.addEvent('domready', function(){
	$E("#calculate-workout").addEvent('click', function(){
		
		var weight_start = $E("#weight-start").value;
		var weight_end = $E("#weight-end").value;
		var weight_lost = Math.max(0,parseFloat(weight_start) - parseFloat(weight_end));
		var fluid_consumed = $E("#fluid-consumed").value;
		var workout_duration = $E("#workout-duration").value;		
	
		var answer = (parseFloat(weight_lost) + parseFloat(fluid_consumed)) / (parseFloat(workout_duration)/60);
		var fluidlost = (parseFloat(weight_lost) + parseFloat(fluid_consumed));

		if( isNaN(answer) || isNaN(fluidlost) ) {
			$E("#workout-answer").innerHTML = "<p class='error'>You must enter all of the information to calculate your sweat rate</p>";
		} else {
			$E("#workout-answer").innerHTML = '<img src="/mmlib/images/ei/spinner.gif" />';
			
			window.setTimeout(function() {
				$E("#workout-answer").innerHTML = "<p class='answer'>During your workout you lost <span class='num'>"+fluidlost.toFixed(2)+"</span>  litres of sweat, which means your hourly sweat rate is <strong><span class='num'>" + answer.toFixed(2) + "</span> litres per hour</strong></p>";
			},2000,fluidlost,answer);
		}

	});

});