// form checker
function checkFormRequired( oForm )
{
	/*
		Select box always selects the first option, when no default selected item is present.
		This function checks if selected option is 0 (first one).
		If so, no option was selected.
		
		For this to work correctly, place a dummy option in select object.
	*/
	//var oForm=document.thisForm; // the form object
	var strReturn=''; // string used to store error msg in
	// loop every element in form
	for (var intCounter=0; intCounter<oForm.length;intCounter++)
	{
		var oFormItem = oForm.elements[intCounter] ;
		// check if element is required
		if (oFormItem.name.substring(0,9)=='required_'){
			// if element is 'text','textarea','select' check it
			if (((oFormItem.type=="text"||oFormItem.type=="textarea")&&oFormItem.value=='')||((oFormItem.type.toString().charAt(0)=="s")&&(oFormItem.selectedIndex==0)))
			{
				if (strReturn==''){strReturn='De volgende velden zijn niet ingevoerd:\n\n';}
				var strName = oFormItem.name.substring(9,oFormItem.name.length)
				var strFName = oFormItem.type.toString().charAt(0);
				strReturn += strName+' is niet '+(strFName=='t'?'ingevuld':'geselecteerd')+'.\n' ;
			}
		}
	}
	if (strReturn!='')
	{
		alert(strReturn);
	} else {
		//remove required tag from names, this way the reciever (asp-script?) doesn't need to remove them
		for (var intCounter=0; intCounter<oForm.length;intCounter++)
		{
			var oFormItem = oForm.elements[intCounter] ;
			// check if element is required
			if (oFormItem.name.substring(0,9)=='required_'){
				oFormItem.name = oFormItem.name.substring(9,oFormItem.name.length);
			}
		}
		//post this form
		oForm.submit();
	}
}
// common functions
function getObj(name)
{
  if (document.getElementById)
  {
  	this.obj = document.getElementById(name);
	this.style = document.getElementById(name).style;
  }
  else if (document.all)
  {
	this.obj = document.all[name];
	this.style = document.all[name].style;
  }
  else if (document.layers)
  {
   	this.obj = document.layers[name];
   	this.style = document.layers[name];
  }
}

function ShowHideMenu(whichone) {
	for (i=0; i<1; i++) {
		 NavMenu = new getObj('Layer'+(i+3));
		 if (((i+3)==whichone) && (whichone!=0)) {
		 	NavMenu.style.visibility="visible"
			 } else {
	 		NavMenu.style.visibility="hidden"
			}
		}
}