function validateFormOnSubmit(theForm) {
var reason = "";

  reason += validatefname(theForm.fname);
  reason += validatesname(theForm.sname);
  reason += validateaddress1(theForm.address1);
  reason += validatepostcode(theForm.postcode);
  reason += validatecontact(theForm.contact);
  reason += validateEmail(theForm.emailcustomer);
  reason += validatepetsname(theForm.petsname);
  reason += validatespecies(theForm.species);
  reason += validatedrug(theForm.drug);
  reason += validatedosage(theForm.dosage);
  reason += validatequantity(theForm.quantity);
  reason += validateinforead(theForm.inforead);
      
  if (reason != "") {
    alert("Some fields need correction:\n" + reason);
    return false;
  }

  return true;
}
function validatefname(fld) {
    var error = "";
 
    if (fld.value.length == 0) {
        fld.style.background = '#FFFFFF'; error = "Please enter your First Name.\n"
    } else {
        fld.style.background = 'White';
    }
    return error;  
}

function validatesname(fld) {
    var error = "";
 
    if (fld.value.length == 0) {
        fld.style.background = '#FFFFFF'; error = "Please enter your Surname.\n"
    } else {
        fld.style.background = 'White';
    }
    return error;  
}

function validateaddress1(fld) {
    var error = "";
 
    if (fld.value.length == 0) {
        fld.style.background = '#FFFFFF'; error = "Please enter your Address.\n"
    } else {
        fld.style.background = 'White';
    }
    return error;  
}

function validatepostcode(fld) {
    var error = "";
 
    if (fld.value.length == 0) {
        fld.style.background = '#FFFFFF'; error = "Please enter your Postcode.\n"
    } else {
        fld.style.background = 'White';
    }
    return error;  
}

function validatecontact(fld) {
    var error = "";
 
    if (fld.value.length == 0) {
        fld.style.background = '#FFFFFF'; error = "Please enter at least 1 Contact Number.\n"
    } else {
        fld.style.background = 'White';
    }
    return error;  
}

function validatepetsname(fld) {
    var error = "";
 
    if (fld.value.length == 0) {
        fld.style.background = '#FFFFFF'; error = "Please enter your Pets Name.\n"
    } else {
        fld.style.background = 'White';
    }
    return error;  
}

function validatespecies(fld) {
    var error = "";
 
    if (fld.value.length == 0) {
        fld.style.background = '#FFFFFF'; error = "Please enter a Species.\n"
    } else {
        fld.style.background = 'White';
    }
    return error;  
}

function validatedrug(fld) {
    var error = "";
 
    if (fld.value.length == 0) {
        fld.style.background = '#FFFFFF'; error = "Please enter Drug Name.\n"
    } else {
        fld.style.background = 'White';
    }
    return error;  
}

function validatedosage(fld) {
    var error = "";
 
    if (fld.value.length == 0) {
        fld.style.background = '#FFFFFF'; error = "Please enter Dosage Currently Administered.\n"
    } else {
        fld.style.background = 'White';
    }
    return error;  
}

function validatequantity(fld) {
    var error = "";
 
    if (fld.value.length == 0) {
        fld.style.background = '#FFFFFF'; error = "Please enter Quantity required.\n"
    } else {
        fld.style.background = 'White';
    }
    return error;  
}


function validateinforead(fld) {
    var error = "";
 
    if (fld.checked == false) {
        fld.style.background = '#FFFFFF'; error = "Please confirm you have read the required information.\n"
    } else {
        fld.style.background = 'White';
    }
    return error;  
}

function trim(s)
{
  return s.replace(/^\s+|\s+$/, '');
}
function validateEmail(fld) {
    var error="";
    var tfld = trim(fld.value);                        // value of field with whitespace trimmed off
    var emailFilter = /^[^@]+@[^@.]+\.[^@]*\w\w$/ ;
    var illegalChars= /[\(\)\<\>\,\;\:\\\"\[\]]/ ;
   
    if (fld.value == "") {
        fld.style.background = '#FFFFFF'; error = "Please enter an Email Address.\n";
    } else if (!emailFilter.test(tfld)) {              //test email for illegal characters
        fld.style.background = '#FFFFFF'; error = "Please enter a valid Email Address.\n";
    } else if (fld.value.match(illegalChars)) {
        fld.style.background = '#FFFFFF'; error = "The Email Address contains illegal characters.\n";
    } else {
        fld.style.background = 'White';
    }
    return error;
}