function checkform()
{
	if(document.getElementById('name').value.length == 0)
	{
		alert("Please type your name.");
		document.getElementById('name').focus();
		return false;
	}
	if(document.getElementById('email').value.length == 0)
	{
		
		alert("Please type your email address.");
		document.getElementById('email').focus();
		return false;
	}
	if(document.getElementById('email').value.length > 0)
	{

	var reg = /^([A-Za-z0-9_\-\.])+\@([A-Za-z0-9_\-\.])+\.([A-Za-z]{2,4})$/;
		   var address = document.getElementById('email').value;
   		if(reg.test(address) == false) {
			alert("Invalid format. Please type correct email address here.");
			document.getElementById('email').focus();
			return false;
			}	
	}
	if(document.getElementById('tel').value.length == 0)
	{
		alert("Please type your telephone number.");
		document.getElementById('tel').focus();
		return false;
	}
	if(document.getElementById('tel').value.length > 0)
	{
		var t = document.getElementById('tel').value;
		var regexNum = /^\d+$/;
		if(!regexNum.test(t))
		{
			alert('Invalid format. Please use numeric values only.');		
			document.getElementById('tel').focus();
			return false;
		}
	}
	
	
	if(document.getElementById('besttime').value.length == 0)
	{
		alert("Please type your best time to contact here.");
		document.getElementById('besttime').focus();
		return false;
	}
	document.contactform.submit();
}