function valid(form) {
  if (form.naam.value=='' || form.email.value=='' || form.opmerkingen.value=='') {
    alert("Please fill in all fields.");
    return false;
  } 
}

window.onload = init;

/* float in script - Copyright 2005 by Stefaan Colman */

var x = 0;
var y = 0;
var w = 0;
var h = 0;
var visible = false;
var step = 10;
var timein = 10;
var timeout = 10;

function init () {
	var visible = false;
  loaddata ();
  var content = document.getElementById ("content");
  content.onmouseover = movein;
  content.onmouseout = moveout;
  var el = document.getElementById ("glijdertje");
	var starth = h - el.offsetHeight
  el.style.top = starth + "px";
	el.style.left = "2px";
  window.onresize = loaddata; // zorgen dat de data aangepast wordt als de venstergrootte veranderd
}

function loaddata () {
  var content = document.getElementById ("content");
  x = findPosX (content);
  y = findPosY (content);
  w = content.offsetWidth;
  h = content.offsetHeight; // border aftrekken nog?
}

function movein (e) {
  if (! e) var e = window.event;
  if (! visible) {
    visible = true;
    flyin ();
  }
}

function moveout (e) {
  if (! e) var e = window.event;
  if (visible) {
    if (e.pageX || e.pageY) {
      posx = e.pageX;
      posy = e.pageY;
    }
    else if (e.clientX || e.clientY) {
      posx = e.clientX + document.body.scrollLeft;
      posy = e.clientY + document.body.scrollTop;
    }
    if (posx < x || posx > x + w || posy < y || posy > y + h) {
      visible = false;
      flyout ();
    }
  }
}
function flyout () {
  if (! visible) {
    var el = document.getElementById ("glijdertje");
    var top = el.style.top.substring (0, el.style.top.length - 2) * 1;
    for (var i = 0; i < step; i++) {
      top++;
      el.style.top = top + "px";
    }
    if (top < h) {
      setTimeout ("flyout ()", timeout);      
    } else {
      el.style.top = h + "px";
	}
  }
}

function flyin () {
  if (visible) {
    var el = document.getElementById ("glijdertje");
    var top = el.style.top.substring (0, el.style.top.length - 2) * 1;
    for (var i = 0; i < step; i++) {
	    if (top > (h - el.offsetHeight + 10)) {
	      top--;
	      el.style.top = top + "px";
		}
    }
    if (top > (h - el.offsetHeight+10)) {
      setTimeout ("flyin ()", timein);
    } else {
		var maxtop = h - el.offsetHeight;
      el.style.top = maxtop + "px";
	}
  }
}

// hulpfuncties
function findPosX (obj) {
  var curleft = 0;
  if (obj.offsetParent)  {
    while (obj.offsetParent) {
      curleft += obj.offsetLeft
      obj = obj.offsetParent;
    }
  }
  else if (obj.x)
    curleft += obj.x;
  return curleft;
}
  
function findPosY (obj) {
  var curtop = 0;
  if (obj.offsetParent) {
    while (obj.offsetParent) {
      curtop += obj.offsetTop
      obj = obj.offsetParent;
    }
  }
  else if (obj.y)
    curtop += obj.y;
  return curtop;
}