function check_pname() {
	var pfname = document.getElementById('element_1_1');
	var plname = document.getElementById('element_1_2');
	var pname = document.getElementById('pname');
	if (pfname.value.length == 0 || plname.value.length == 0) {
		pname.style.visibility="visible";
		return false;
	} else {
		pname.style.visibility="hidden";
		return true;
	}
	}

function check_otype() {
	var wvalue = document.getElementById('element_6');
	var otype = document.getElementById('otype');
	if (ovalue.value.length == 0) {
		otype.style.visibility="visible";
		return false;
	} else {
		otype.style.visibility="hidden";
		return true;
	}
}

function check_otitle() {
	var wvalue = document.getElementById('element_7');
	var otitle = document.getElementById('otitle');
	if (wvalue.value.length == 0) {
		otitle.style.visibility="visible";
		return false;
	} else {
		otitle.style.visibility="hidden";
		return true;
	}
}

function check_date() {
	var mm = document.getElementById('element_8_1');
	var dd = document.getElementById('element_8_2');
	var year = document.getElementById('element_8_3');
	var date = document.getElementById('date');
	var numericExpression = /^[0-9]+$/;
	if (mm.value.match(numericExpression) && mm.value > 0 && mm.value < 13 && 
		dd.value.match(numericExpression) && dd.value > 0 && dd.value < 32 && 
		year.value.match(numericExpression) && year.value > 2007 && year.value < 2010) {
		date.style.visibility="hidden";
		return true;
	} else {
		date.style.visibility="visible";
		return false;
	}
}

function check_hours() {
	var ch = document.getElementById('element_9');
	var hours = document.getElementById('hours');
	var numericExpression = /^[0-9]+$/;
	if (ch.value.match(numericExpression) && ch.value > 0 && ch.value < 12) {
		hours.style.visibility="hidden";
		return true;
	} else {
		hours.style.visibility="visible";
		return false;
	}
}


function check_who() {
	var wvalue = document.getElementById('element_10');
	var wtitle = document.getElementById('who');
	if (wvalue.value.length == 0) {
		wtitle.style.visibility="visible";
		return false;
	} else {
		wtitle.style.visibility="hidden";
		return true;
	}
}
function validate() {
	var pcheck = check_pname();
	var wtitle = check_otitle();
	var date = check_date();
	var hours = check_hours();
	var who = check_who();
	var val = pcheck && wtitle && date && hours && who;
	if (!val) alert ("Please enter the required fields.");
	return val;
}