function checkFields() {
missinginfo = "";
if (document.warranty.firstname.value == "") {
missinginfo += "\n     -  First Name";
}
if (document.warranty.lastname.value == "") {
missinginfo += "\n     -  Last Name";
}
if (document.warranty.address1.value == "") {
missinginfo += "\n     -  Address Line 1";
}
if (document.warranty.city.value == "") {
missinginfo += "\n     -  City";
}
if (document.warranty.state.value == ""){
missinginfo += "\n     -  State";
}
if (document.warranty.zip.value == "") {
missinginfo += "\n     -  Zip Code";
}
if (document.warranty.phone.value == "") {
missinginfo += "\n     -  Phone";
}
if (document.warranty.modelnumber.value == "") {
missinginfo += "\n     -  Model Number";
}
if (document.warranty.serialnumber.value == "") {
missinginfo += "\n     -  Serial Number";
}
if (document.warranty.dop.value == "") {
missinginfo += "\n     - Purchase Date";
}
if (document.warranty.wherepurchased.value == "") {
missinginfo += "\n     -  Where Purchased";
}

if (missinginfo != "") {
missinginfo ="\nThe following required fields have been left blank:\n" +
missinginfo + "\n_____________________________                   \n" +
"\nPlease complete these fields and press submit.";
alert(missinginfo);
return false;
}
else return true;
}