var MSGTIMER = 20;
var MSGSPEED = 5;
var MSGOFFSET = 3;
var MSGHIDE = 3;

function validate(form) {
	var emailRegex = /^[\w-\.]+@([\w-]+\.)+[\w-]{2,4}$/;
	var phoneRegex = new RegExp(/\d{3} \d{3} \d{4}/);
	
	for(var i = 0; i < form.elements.length; i++)
	{
		if(form.elements[i].type == "radio" && form.elements[i].className == "require"){
			var name = form.elements[i].name;
			var checked = false;
			
			while( form.elements[i].name == name )
			{
				if( form.elements[i].checked )
					checked = true;
				i++;
			}
			i--;
			
			if(!checked)
			{
				inlineMsg(form.elements[i], "Please select an option", 1);
				return false;
			}
		}
		else if(form.elements[i].className == "require" && form.elements[i].type == "checkbox" && !form.elements[i].checked){
			inlineMsg(form.elements[i], "Please check all required boxes", 1);
			return false;
		}
		else if(form.elements[i].tagName == "INPUT" && form.elements[i].type == "text" && form.elements[i].getAttribute("var") == "phone" && form.elements[i].className == "require")
		{
			if(!form.elements[i].value.match(phoneRegex)){
				inlineMsg(form.elements[i], "Please enter a phone number with the pattern XXX YYY ZZZZ.");
				return false;
			}
		}
		else if(form.elements[i].tagName == "INPUT" && form.elements[i].type == "text" && form.elements[i].className == "require" && !form.elements[i].value)
		{
			inlineMsg(form.elements[i], "Please enter a value.");
			return false;
		}
		else if(form.elements[i].tagName == "TEXTAREA" && form.elements[i].className == "require" && !form.elements[i].value)
		{
			inlineMsg(form.elements[i], "Please enter a value.");
			return false;
		}
	}
	return true;
}

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 = target;
  targetdiv.focus();
  var targetheight = targetdiv.offsetHeight;
  var targetwidth = targetdiv.offsetWidth;
  var topposition = topPosition(targetdiv) - ((msgheight - targetheight) / 2);
  var leftposition = leftPosition(targetdiv) + targetwidth + 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 * 3000));
}

// 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 = "http://reslife.cofc.edu/graphics/msg_arrow.gif"; 
}