function validateCarInput(form) {
    if(form.ct.value == "") {
      alert("Please city, STATE.");
      form.ct.focus();
      return false;
    }

    var d = new Date();
    var d1;
    var d2; 

    if(form.d1.value == "") {
      alert("Please enter a valid Check-in date.");
      return false;
    }

    if(form.d2.value == "") {
      alert("Please enter a valid Check-out date.");
      return false;
    }
  
    var d1 = new Date(form.d1.value);
    var d2 = new Date(form.d2.value);

    //Make sure the dates created were valid - if not, return
    if(d1.toString() == "Invalid Date") {
      alert("Please enter a valid Check-in date in the form mm/dd/yyyy.");
      return false;
    }

    if(d2.toString() == "Invalid Date") {
      alert("Please enter a valid Return date in the form mm/dd/yyyy.");
      return false;
    }

    if(compareDates(d1, d) == false) {
      alert("Check-in date is not valid - please re-enter.");
      return false;
    }
    if(compareDates(d2, d1) == false) {
      alert("Check-out date is not valid - please re-enter.");
      return false;
    }
  
    //Format Dates Correctly:
    var yyyy1 = d1.getFullYear();
    var mm1 = d1.getMonth() + 1;
    var dd1 = d1.getDate();
    form.d1.value = mm1 + "/" + dd1 + "/" + yyyy1;
  

    var yyyy2 = d2.getFullYear();
    var mm2 = d2.getMonth() + 1;
    var dd2 = d2.getDate();
    form.d2.value = mm2 + "/" + dd2 + "/" + yyyy2;


    return true;
  }

  function compareDates(date1, date2) {
    if(date1 == null || date2 == null) {
      return false;
    }

    if(date1.getFullYear() < date2.getFullYear() || (date1.getFullYear() == date2.getFullYear() && (date1.getMonth() < date2.getMonth() || (date1.getMonth() == date2.getMonth() && (date1.getDate() < date2.getDate()))))) {
      
      return false;
    }
    else {
      return true;
    }
  }