function checkFields(strForm) 
{
	with(strForm) 
  {
		if(colorSelect.value == "") 
    {
			alert("Please select a color");
			return false;
		}

		if(modelSelect.value == "") 
    {
			alert("Please select a model");
			return false;
		}

		if(sizeSelect.value == "") 
		{
			alert("Please select a size");
			return false;
		}
    //check if valid combination 22=48 23=50 24=52
    if ((sizeSelect.value == 22) || (sizeSelect.value == 23) || (sizeSelect.value == 24))
    {
        if ((modelSelect.value != 5) || (colorSelect.value != "Khaki"))
        {
          alert ("Sizes 48, 50, and 52 are only for model M2P with color Khaki");
          return false;
        }
    }

		// inseam not always included, so only do the validation if the field is included in the DOM
		if (document.getElementById('inseamsize'))
		{
		    if(inseamsize.value == "") {
			    alert("Please select an inseam size");
			    return false;
		    }
		}

		if(textfield.value == "") 
    {
			alert("Please enter the quantity");
			eval(textfield).focus();
			return false;
		}
		if(isNaN(textfield.value)) 
    {
			alert("Quantity must be numeric");
			eval(textfield).focus();
			return false;
		}
		else if (textfield.value < 1)
		{
		    alert("Quantity must be an integer greater than 0");
			eval(textfield).focus();
			return false;
		}
		else if (!isInt(textfield.value))
		{
		    alert("Quantity must be an integer greater than 0");
			eval(textfield).focus();
			return false;
		}
		if(style.value == "") 
    {
			alert("Please select a style");
			return false;
		}
  }
	
	return true;
}
 function isInt(x) {
   var y=parseInt(x);
   if (isNaN(y)) return false;
   return x==y && x.toString()==y.toString();
 }
function checkFields2(strForm) {
	with(strForm) {
		if(bfname.value == "") {
			alert("Please enter the first name");
			eval(bfname).focus();
			return false;
		}
		if(blname.value == "") {
			alert("Please enter the last name");
			eval(blname).focus();
			return false;
		}
		if(baddress.value == "") {
			alert("Please enter the address");
			eval(baddress).focus();
			return false;
		}
		if(bcity.value == "") {
			alert("Please enter the city");
			eval(bcity).focus();
			return false;
		}
		if(bstate.value == "") {
			alert("Please enter the state");
			eval(bstate).focus();
			return false;
		}
		if(bzip.value == "") {
			alert("Please enter the zip");
			eval(bzip).focus();
			return false;
		}
		if(bphone.value == "") {
			alert("Please enter the phone");
			eval(bphone).focus();
			return false;
		}
		if(bemail.value == "") {
			alert("Please enter the email");
			eval(bemail).focus();
			return false;
		}
		if(!isValidEmailAddress(bemail.value)) {
			alert("Please enter a valid email");
			eval(bemail).focus();
			return false;
		}

		if(cctype.value == "") {
			alert("Please enter the credit card type");
			eval(cctype).focus();
			return false;
		}

		if(ed1.value == "") {
			alert("Please enter the expiration date");
			eval(ed1).focus();
			return false;
		}

		if(ed2.value == "") {
			alert("Please enter the expiration date");
			eval(ed2).focus();
			return false;
		}
		
		if(cvv.value == "") {
			alert("Please enter the CVV number");
			eval(cvv).focus();
			return false;
		}

		if(ccnumber.value == "") {
			alert("Please enter the credit card number");
			eval(ccnumber).focus();
			return false;
		}

		if(shipmethod.value == "") {
			alert("Please enter the shipping method");
			eval(shipmethod).focus();
			return false;
		}
	}
	return true;
}

function checkFields3(strForm) 
{
	with(strForm) {
		if(fname.value == "") {
			alert("Please enter the first name");
			eval(fname).focus();
			return false;
		}
		if(lname.value == "") {
			alert("Please enter the last name");
			eval(lname).focus();
			return false;
		}
		if(address.value == "") {
			alert("Please enter the address");
			eval(address).focus();
			return false;
		}
		if(city.value == "") {
			alert("Please enter the city");
			eval(city).focus();
			return false;
		}
		if(state.value == "") {
			alert("Please enter the state");
			eval(state).focus();
			return false;
		}
		if(zip.value == "") {
			alert("Please enter the zip");
			eval(zip).focus();
			return false;
		}
		if(phone.value == "") {
			alert("Please enter the phone");
			eval(phone).focus();
			return false;
		}
		if(email.value == "") {
			alert("Please enter the email");
			eval(email).focus();
			return false;
		}
		if(!isValidEmailAddress(email.value)) {
			alert("Please enter a valid email");
			eval(email).focus();
			return false;
		}
	}
	return true;
}

function isValidEmailAddress(emailAddressToCheck) 
{
    var regex = /^[a-zA-Z0-9._-]+@([a-zA-Z0-9.-]+\.)+[a-zA-Z0-9.-]{2,4}$/;
    return regex.test(emailAddressToCheck);
}