// Registration Form Validation
function validateRegistration(form_id) {
 var forename = document.forms[form_id].elements['FORENAME'].value;
 if(forename == "") { alert('You must specify a forename.'); return false; }
 var surname = document.forms[form_id].elements['SURNAME'].value;
 if(surname == "") { alert('You must specify a surname.'); return false; }

 var yearJoin = document.forms[form_id].elements['YEAR_JOIN'].value;
 if(yearJoin == "NULL") { alert('You must specify the year you joined the band.'); return false; }
 var yearLeft = document.forms[form_id].elements['YEAR_LEFT'].value;
 if(yearLeft == "NULL") { alert('You must specify the year you left the band.'); return false; }

 var instrument = document.forms[form_id].elements['INSTRUMENT'].value;
 if(instrument == "NULL") { alert('You must specify the instrument you played.'); return false; }

 var radios = document.forms[form_id].elements['ATTEND']; var itemchecked = false;
 for(var i = 0 ; i < radios.length ; ++i) { if(radios[i].checked) { itemchecked = true; break; } }
 if(!itemchecked) { alert('Please specify your availability to attend at the reunion.'); return false; }

 var radios = document.forms[form_id].elements['AVAILABLE']; var itemchecked = false;
 for(var i = 0 ; i < radios.length ; ++i) { if(radios[i].checked) { itemchecked = true; break; } }
 if(!itemchecked) { alert('Please specify your availability to perform at the reunion.'); return false; }

 var reg = /^([A-Za-z0-9_\-\.])+\@([A-Za-z0-9_\-\.])+\.([A-Za-z]{2,4})$/;
 var email = document.forms[form_id].elements['EMAIL'].value;
 if(email == "") { alert('You must specify an email address.'); return false; }
 if(reg.test(email) == false) { alert('Invalid Email Address'); return false; }
}