// form validation function //
function validateSub(form) {
  var title = form.title.value;
  var firstname = form.firstname.value;
  var speciality = form.speciality.value;
  var organisation = form.organisation.value;
  var jobtitle = form.jobtitle.value;
  var address = form.address.value;
  var postcode = form.postcode.value;
  var telephone = form.telephone.value;
  var email = form.email.value;
  var emailRegex = /^[\w-\.]+@([\w-]+\.)+[\w-]{2,4}$/;
  var verify = form.verify.value;


  if(title == "") {
    inlineMsg('title','<b>Please tell us your title.</b>',2);
    return false;
  }

  if(firstname == "") {
    inlineMsg('firstname','<b>Please tell us your name.</b>',2);
    return false;
  }
  
  if(speciality == "") {
    inlineMsg('speciality','<b>Please tell us your speciality.</b>',2);
    return false;
  }
  
  if(organisation == "") {
    inlineMsg('organisation','<b>Please tell us your hospital/organisation.</b>',2);
    return false;
  }
  
  if(jobtitle == "") {
    inlineMsg('jobtitle','<b>Please tell us your job title.</b>',2);
    return false;
  }

  if(address == "") {
    inlineMsg('address','<b>Please tell us your address.</b>',2);
    return false;
  }
  
  if(postcode == "") {
    inlineMsg('postcode','<b>Please tell us your postcode.</b>',2);
    return false;
  }
 
  if(telephone == "") {
    inlineMsg('telephone','<b>Please tell us your telephone.</b>',2);
    return false;
  }

  if(email == "") {
    inlineMsg('email','<b>Please tell us your email.</b>',2);
    return false;
  }
  
  if(!email.match(emailRegex)) {
    inlineMsg('email','<b>You have entered an invalid email.</b>',2);
    return false;
  }

  if(verify == "") {
    inlineMsg('verify','<b>Please enter validation colour shown.<\/b>',2);
    return false;
  }  
  if(verify != "red") {
    inlineMsg('verify','<b>Sorry, validation entered is incorrect.<\/b>',2);
    return false;
  }  
  
  return true;
}

// START OF MESSAGE SCRIPT //

var MSGTIMER = 20;
var MSGSPEED = 10;
var MSGOFFSET = 0;
var MSGHIDE = 5;

// build out the divs, set attributes and call the fade function //
function inlineMsg(target,string,autohide) {
  var msg;
  var msgcontent;
  if(!document.getElementById('msg')) {
    msg = document.createElement('div');
    msg.id = 'msg';
    msgcontent = document.createElement('div');
    msgcontent.id = 'msgcontent';
    document.body.appendChild(msg);
    msg.appendChild(msgcontent);
    msg.style.filter = 'alpha(opacity=0)';
    msg.style.opacity = 0;
    msg.alpha = 0;
  } else {
    msg = document.getElementById('msg');
    msgcontent = document.getElementById('msgcontent');
  }
  msgcontent.innerHTML = string;
  msg.style.display = 'block';
  var msgheight = msg.offsetHeight;
  var targetdiv = document.getElementById(target);
  targetdiv.focus();
  var targetheight = targetdiv.offsetHeight;
  var targetwidth = targetdiv.offsetWidth;
  var topposition = topPosition(targetdiv) + (30);
  var leftposition = leftPosition(targetdiv) + MSGOFFSET;
  msg.style.top = topposition + 'px';
  msg.style.left = leftposition + 'px';
  clearInterval(msg.timer);
  msg.timer = setInterval("fadeMsg(1)", MSGTIMER);
  if(!autohide) {
    autohide = MSGHIDE;  
  }
  window.setTimeout("hideMsg()", (autohide * 5000));
}

// hide the form alert //
function hideMsg(msg) {
  var msg = document.getElementById('msg');
  if(!msg.timer) {
    msg.timer = setInterval("fadeMsg(0)", MSGTIMER);
  }
}

// face the message box //
function fadeMsg(flag) {
  if(flag == null) {
    flag = 1;
  }
  var msg = document.getElementById('msg');
  var value;
  if(flag == 1) {
    value = msg.alpha + MSGSPEED;
  } else {
    value = msg.alpha - MSGSPEED;
  }
  msg.alpha = value;
  msg.style.opacity = (value / 100);
  msg.style.filter = 'alpha(opacity=' + value + ')';
  if(value >= 99) {
    clearInterval(msg.timer);
    msg.timer = null;
  } else if(value <= 1) {
    msg.style.display = "none";
    clearInterval(msg.timer);
  }
}

// calculate the position of the element in relation to the left of the browser //
function leftPosition(target) {
  var left = 0;
  if(target.offsetParent) {
    while(1) {
      left += target.offsetLeft;
      if(!target.offsetParent) {
        break;
      }
      target = target.offsetParent;
    }
  } else if(target.x) {
    left += target.x;
  }
  return left;
}

// calculate the position of the element in relation to the top of the browser window //
function topPosition(target) {
  var top = 0;
  if(target.offsetParent) {
    while(1) {
      top += target.offsetTop;
      if(!target.offsetParent) {
        break;
      }
      target = target.offsetParent;
    }
  } else if(target.y) {
    top += target.y;
  }
  return top;
}

// preload the arrow //
if(document.images) {
  arrow = new Image(7,80); 
  arrow.src = "images/msg_arrow.gif"; 
}