function round(number,X) {
// rounds number to X decimal places, defaults to 2
X = (!X ? 2 : X);
return Math.round(number*Math.pow(10,X))/Math.pow(10,X);
}

function jumpBox(list) {
   location.href = list.options[list.selectedIndex].value
   }

function compute(form)  {
   var milesPerMo = form.avgMiles.value *30.4;
   var mpgcalc = ((form.endOd.value - form.begOd.value) / form.gallons.value);
   var moGascalc = (((form.avgMiles.value * 30.4) / mpgcalc) * form.ppGal.value);
   form.mpg.value = round(mpgcalc);
   form.moGas.value = round(moGascalc);
   form.yrGas.value = round(moGascalc * 12);
   
   if(form.mpg2.value > 0) {
              var moGas2calc = ((milesPerMo / form.mpg2.value) * form.ppGal.value);
              form.moGas2.value = round(moGas2calc);
              form.yrGas2.value =  round(moGas2calc * 12);
              var annualsave = form.yrGas.value - form.yrGas2.value;
              form.save.value = ("If you switch to a car that gets " + form.mpg2.value + " mpg, you'll save $" + parseInt(annualsave,10) + " per year.")
              }
              else {
              form.moGas2.value = "";
              form.yrGas2.value = "";
              form.save.value = ("Now enter a higher mpg to compare to your car's present mpg.");
              }
   } 

function ClearForm(form)  {
   form.begOd.value = "";
   form.endOd.value = "";
   form.avgMiles.value = "";
   form.gallons.value = "";
   form.ppGal.value = "";
   form.mpg.value = "";
   form.moGas.value = "";
   form.yrGas.value = "";
   form.mpg2.value = "";
   form.moGas2.value = "";
   form.yrGas2.value = "";
   form.save.value = "";
   
   }