function formShowTab(curTab) {
	//hide all divs
	var divs = document.getElementsByTagName('div');
	for ( var i = 0; i < divs.length; i++ )
	{
		if (divs[i].className == 'formMainTxt')
		divs[i].style.display = 'none';
	}
	//show selected div
	document.getElementById('tab_'+curTab).style.display = 'block';

	//make other tabs inactive
	var aTags = document.getElementsByTagName('a');
	for ( var i = 0; i < aTags.length; i++ )
	{
		if (aTags[i].className == 'current')
			aTags[i].className = '';
	}

	//make this tab active
	document.getElementById('tab_btn'+curTab).className = 'current';

}

function disableTab(tabNum) {
	document.getElementById('tab_btn'+tabNum).className = 'disabled';
	document.getElementById('tab_btn'+tabNum).onclick = 'function() {}';
	document.getElementById('tab_btn'+tabNum).removeAttribute("onclick");
	document.getElementById('tab_btn'+tabNum).title = 'Gebruik de knoppen onderaan het formulier';
}

function enableTab(tabNum) {
	document.getElementById('tab_btn'+tabNum).className = '';
	document.getElementById('tab_btn'+tabNum).onclick = function() {goToTab(tabNum, 'tabjump');}
	document.getElementById('tab_btn'+tabNum).title = '';
}

function goToIndex() {
	go(indexPageURI);
}

function checkForm() {
	//check if submit-button is pressed (not pressed on enter in INPUT-field)
	if (formIsReadyToSave == true) { return true; } else { return false;}
}

function setButton(xCompId, xButton) {
	//two-state button!
	(xButton == 1) ? xPressedClass = 'button_p' : xPressedClass = 'button'
	document.getElementById('knop'+xCompId+'_1').className = xPressedClass;
	(xButton == 2) ? xPressedClass = 'button_p' : xPressedClass = 'button'
	document.getElementById('knop'+xCompId+'_2').className = xPressedClass;
	(xButton == 3) ? xPressedClass = 'button_p' : xPressedClass = 'button'
	document.getElementById('knop'+xCompId+'_3').className = xPressedClass;
	(xButton == 4) ? xPressedClass = 'button_p' : xPressedClass = 'button'
	document.getElementById('knop'+xCompId+'_4').className = xPressedClass;
	(xButton == 5) ? xPressedClass = 'button_p' : xPressedClass = 'button'
	document.getElementById('knop'+xCompId+'_5').className = xPressedClass;

  document.getElementById('answer'+xCompId+'_'+xButton).checked = true;
}

function goToTab(curTab, direction) {
	var formOkay, tabToCheck;
	if (direction != 'prev') {
		//check input field of current tab before jumping
		if (direction == 'tabjump' || direction == 'overview') {
			//controleren van actieve tab als andere tab geslecteerd wordt
			tabToCheck = activeTab;
		} else {
			//controleren van actieve tab als op volgende of vorige geklikt wordt
			tabToCheck = curTab;
		}

		if (tabToCheck==1) { formOkay = inputCheck_tab1(); }
		else if (tabToCheck==2) { formOkay = inputCheck_tab2(); }
		else if (tabToCheck==3) { formOkay = inputCheck_tab3(); }
		else if (tabToCheck==4) { formOkay = inputCheck_tab4(); }
		else if (tabToCheck==5) { formOkay = inputCheck_tab5(); }
		else if (tabToCheck==6) { formOkay = inputCheck_tab6(); }
		else if (tabToCheck==7) { formOkay = inputCheck_tab7(); }
		else if (tabToCheck==8) { formOkay = inputCheck_tab8(); }
		else if (tabToCheck==9) { formOkay = inputCheck_tab9(); }
		else if (tabToCheck==10) { formOkay = inputCheck_tab10(); }
	}

	if (formOkay == 0 || formOkay == undefined) {
		//jump to specified tab
		if (direction == 'prev') {
			formShowTab(curTab-1);
			activeTab = curTab-1;
		} else if (direction == 'next') {
			enableTab(curTab+1);
			formShowTab(curTab+1);
			activeTab = curTab+1;
		} else if (direction == 'tabjump') {
			formShowTab(curTab);
			activeTab = curTab;
		}
	}
	window.scrollTo(0,0);
}


function goToOverview(curTab, direction) {
	//open overview tab and show tab
	goToTab(curTab, direction)
	document.getElementById('tab_btn'+activeTab).style.display = 'block';

	var htmlOverview, htmlButtons, oField, maxField;
	htmlButtons = '<td class=column2><input type=button onClick="goToIndex();" name=Annuleren tabindex=-1 value=Annuleren class=submitBTN><input type=submit onClick="formIsReadyToSave=true;" name=Opslaan value=Opslaan class=submitBTN></td><td >&nbsp;</td></tr>'

	htmlOverview = '';
	htmlOverview +=	'<table width=100% border=0 cellspacing=0 cellpadding=0 class=table_light>'
	htmlOverview +=	'<tr><td class=noheight></td><td class=noheight></td><td class=noheight></td></tr>'
	htmlOverview +=	'<tr><td colspan=3><strong>Zijn alle gegevens correct ingevoerd?</strong></td></tr>'
	htmlOverview +=	htmlButtons

	//loop through form elements to display contents of it (USES TITLE ATTRIBUTE OF INPUT-ELEMENTS!)
	maxField = document.forms[0].elements.length;
	for (var iField = 0; iField<maxField; iField++) {
		oField = document.forms[0].elements[iField]
		//only use content of textarea, text, select, radio, checkbox
		if (oField.type.indexOf('textarea') > -1 || oField.type.indexOf('text') > -1) {
			htmlOverview += '<tr><td class=column1>' + oField.title + '</td><td class=column2>' + oField.value + '</td><td>&nbsp;</td></tr>';
		}
		else if (oField.type.indexOf('select') > -1) {
			htmlOverview += '<tr><td class=column1>' + oField.title + '</td><td class=column2>' + oField.options[oField.selectedIndex].innerHTML + '</td><td></td></tr>';
		}
		else if (oField.type.indexOf('radio') > -1 || oField.type.indexOf('checkbox') > -1) {

			var startingIndex = iField;
			var rLength=1;
			selectedVal = '';

			while(oField.type == document.forms[0].elements[iField+1].type && oField.name == document.forms[0].elements[iField+1].name){
				//get length of the box-group
				rLength++
				iField++
			}

			for(g = startingIndex; g < rLength+startingIndex; g++){
				if(document.forms[0].elements[g].checked){
					//add the selected element to the output
					selectedVal += document.forms[0].elements[g].nextSibling.innerHTML + '<br>'
				}
			}

			htmlOverview += '<tr><td class=column1>' + oField.title + '</td><td class=column2>' + selectedVal + '</td><td>&nbsp;</td></tr>';

		}

	}

	htmlOverview +=	htmlButtons
	htmlOverview +=	'<tr><td class=column1>&nbsp;</td><td class=column2>&nbsp;</td><td>&nbsp;</td></tr>'
	htmlOverview +=	'</table>'

	//write the contents of form-fields to overview-tab
	document.getElementById('overviewBlock').innerHTML = htmlOverview;
}