function validate_email(field,alerttxt)
{
with (field)
{
apos=value.indexOf("@");
dotpos=value.lastIndexOf(".");
if (apos<1||dotpos-apos<2) 
  {alert(alerttxt);return false;}
else {return true;}
}
}

function validate_required(field,alerttxt)
{
with (field)
{
if (value==null||value=="" || value== "0")
  {alert(alerttxt);return false;}
else {return true}
}
}

function validate_form(thisform)
{
with (thisform)
{
if (validate_required(first_name,"First name must be filled out!")==false)
  {first_name.focus();return false;}
  
if (validate_required(last_name,"Last name must be filled out!")==false)
  {last_name.focus();return false;}
  
if (validate_required(city,"City must be filled out!")==false)
  {city.focus();return false;}
  
if (validate_required(state,"State must be selected!")==false)
  {state.focus();return false;}
  
if (validate_required(zip_code,"ZIP must be filled out!")==false)
  {zip_code.focus();return false;}
  
if (validate_email(email,"Not a valid e-mail address!")==false)
  {email.focus();return false;}
  
  	if(!document.signUpForm["understand"].checked) {
		alert("You have to click Yes to agree!");
		return false;
	}
}
}