// function that sets form field to 0 if value is omitted
function setToZero(frmfield) {
	var vTemp = frmfield; // set temp variable to hold name of form field.
	
	if(vTemp.value == null || vTemp.value.length == 0) {
		vTemp.value = 0;
	}
}

// Calculate the miles per hour.
function calculate(form)	{
	// zero out hours, minutes, seconds if user does not update values.
	setToZero(form.h);
	setToZero(form.m);
	setToZero(form.s);
	
	// total up hours, minutes and seconds to all equal seconds
	var tot_time = (form.h.value*3600) + (form.m.value*60) + (form.s.value*1);
	
	// make certain time is greater than Zero.
	if (tot_time==0)	{ 
			alert("You must enter a time greater than ZERO SECONDS in order to use this calculator.")
		} else { 
		
			// this portion of code figures the Miles Per Hour
			if (form.distance.value.length==0)	{
		    	alert("You must have a DISTANCE value greater than 0.")
			} else	{
				// if we're dealing with Kilometers, convert kilometers to Miles (so we can figure MPH)
				if(form.distanceType.value == form.distanceType[1].value) {	
					mile_hour = form.distance.value*form.distanceType[1].value;
					kilo_hour = form.distance.value;	
				}
				
				// if we're dealing with Miles, convert kilometers to Miles (so we can figure KPH)
				if(form.distanceType.value == form.distanceType[0].value) {	
					kilo_hour = form.distance.value*form.distanceType[0].value;	
					mile_hour = form.distance.value;
				}
				
			    var mHour = Math.round(	((mile_hour*3600)/tot_time) * 100) /100; 
				var kHour = Math.round( ((kilo_hour*3600)/tot_time) * 100) / 100;

				form.milesPerHour.value= mHour;
				form.kmPerHour.value = kHour;

		}	// End Miles Per Hour code
		
		// Begin Pace Code
		var secs_mile = Math.round((tot_time/mile_hour)*100)/100; 
		var secs_kilo = Math.round((tot_time/kilo_hour)*100)/100;
	    var sec_part = Math.round((secs_mile%60)*100)/100;
		var sec_partK = Math.round((secs_kilo%60)*100)/100;
	    var whole_part = secs_mile - sec_part;
		var whole_partK = secs_kilo - sec_partK;
	    var min_part = whole_part/60;
		var min_partK = whole_partK/60;
		
	    if (sec_part==0)	{	
			form.minPerMile.value= min_part + ":00." + sec_part;	
		} else {
	      if (sec_part < 1)	{
		  	form.minPerMile.value= min_part + ":00" + sec_part; 
	      } else {
	      	if (sec_part < 10)	{
				form.minPerMile.value= min_part + ":0" + sec_part; 
	        } else	{
	          form.minPerMile.value= min_part + ":" + sec_part; 
	        }
	      }	  
		}
		
	    if (sec_partK==0)	{	
			form.minPerKM.value= min_partK + ":00." + sec_partK;	
		} else {
	      if (sec_partK < 1)	{
		  	form.minPerKM.value= min_partK + ":00" + sec_partK; 
	      } else {
	      	if (sec_partK < 10)	{
				form.minPerKM.value= min_partK + ":0" + sec_partK; 
	        } else	{
	          form.minPerKM.value= min_partK + ":" + sec_partK; 
	        }
	      }	  
		}		
	}	  
	return;

}