function getWindowHeight() {
var windowHeight=0;
if (typeof(window.innerHeight)=='number') {
windowHeight=window.innerHeight;
}
else {
if (document.documentElement&&
document.documentElement.clientHeight) {
windowHeight=
document.documentElement.clientHeight;
}
else {
if (document.body&&document.body.clientHeight) {
windowHeight=document.body.clientHeight;
}
}
}
return windowHeight;
}

function setDIVHeight() {
if (document.getElementById) {
	var windowHeight=getWindowHeight();
	if (windowHeight>400) {
	var contElement=document.getElementById('content_box');
	contElement.style.height=windowHeight - 225 + "px";
	}
}
}

window.onresize = function(){
	setDIVHeight();
}

function checksubmit()
{
   if (document.icomosform.email.value == "")
   {
      alert("Please fill in your emailaddress.")
      document.icomosform.email.focus()
      return false
   }
   if (document.icomosform.naam.value == "")
   {
      alert("Please fill in your name.")
      document.icomosform.naam.focus()
      return false
   }
   if (document.icomosform.vraag.value == "")
   {
      alert("Please fill in your question or suggestion.")
      document.icomosform.vraag.focus()
      return false
   }
   return true
}