function checkForm()
			{
				var cname, cemail, csubject, cmessage;
				with(window.document.msgform)
				{
					cname    = sname;
					cemail   = email;
					csubject = subject;
					cmessage = message;
				}
				
				if(trim(cname.value) == '')
				{
					alert('Vui long nhap ho&ten cua Quy khach!');
					cname.focus();
					return false;
				}
				else if(trim(cemail.value) == '')
				{
					alert('Vui long nhap dia chi Email cua Quy khach!');
					cemail.focus();
					return false;
				}
				else if(!isEmail(trim(cemail.value)))
				{
					alert('Dia chi Email cua Quy khach khong dung! Vui long nhap lai!');
					cemail.focus();
					return false;
				}
				else if(trim(csubject.value) == '')
				{
					alert('Vui long nhap tieu de!');
					csubject.focus();
					return false;
				}
				else if(trim(cmessage.value) == '')
				{
					alert('Vui long nhap noi dung!');
					cmessage.focus();
					return false;
				}
				else
				{
					cname.value    = trim(cname.value);
					cemail.value   = trim(cemail.value);
					csubject.value = trim(csubject.value);
					cmessage.value = trim(cmessage.value);
					return true;
				}
			}
			
			//Strip whitespace from the beginning and end of a string Input : a string

		function trim(str)
			{
				return str.replace(/^\s+|\s+$/g,'');
			}
			
			//Check if a string is in valid email format.Returns true if valid, false otherwise.
			
		function isEmail(str)
			{
				var regex = /^[-_.a-z0-9]+@(([-_a-z0-9]+\.)+(ad|ae|aero|af|ag|ai|al|am|an|ao|aq|ar|arpa|as|at|au|aw|az|ba|bb|bd|be|bf|bg|bh|bi|biz|bj|bm|bn|bo|br|bs|bt|bv|bw|by|bz|ca|cc|cd|cf|cg|ch|ci|ck|cl|cm|cn|co|com|coop|cr|cs|cu|cv|cx|cy|cz|de|dj|dk|dm|do|dz|ec|edu|ee|eg|eh|er|es|et|eu|fi|fj|fk|fm|fo|fr|ga|gb|gd|ge|gf|gh|gi|gl|gm|gn|gov|gp|gq|gr|gs|gt|gu|gw|gy|hk|hm|hn|hr|ht|hu|id|ie|il|in|info|int|io|iq|ir|is|it|jm|jo|jp|ke|kg|kh|ki|km|kn|kp|kr|kw|ky|kz|la|lb|lc|li|lk|lr|ls|lt|lu|lv|ly|ma|mc|md|mg|mh|mil|mk|ml|mm|mn|mo|mp|mq|mr|ms|mt|mu|museum|mv|mw|mx|my|mz|na|name|nc|ne|net|nf|ng|ni|nl|no|np|nr|nt|nu|nz|om|org|pa|pe|pf|pg|ph|pk|pl|pm|pn|pr|pro|ps|pt|pw|py|qa|re|ro|ru|rw|sa|sb|sc|sd|se|sg|sh|si|sj|sk|sl|sm|sn|so|sr|st|su|sv|sy|sz|tc|td|tf|tg|th|tj|tk|tm|tn|to|tp|tr|tt|tv|tw|tz|ua|ug|uk|um|us|uy|uz|va|vc|ve|vg|vi|vn|vu|wf|ws|ye|yt|yu|za|zm|zw)|(([0-9][0-9]?|[0-1][0-9][0-9]|[2][0-4][0-9]|[2][5][0-5])\.){3}([0-9][0-9]?|[0-1][0-9][0-9]|[2][0-4][0-9]|[2][5][0-5]))$/i;
				return regex.test(str);
			}


function checkNumber(textBox)
{
	while (textBox.value.length > 0 && isNaN(textBox.value)) {
		textBox.value = textBox.value.substring(0, textBox.value.length - 1)
	}
	
	textBox.value = trim(textBox.value);
/*	if (textBox.value.length == 0) {
		textBox.value = 0;		
	} else {
		textBox.value = parseInt(textBox.value);
	}*/
}

/*
	Check if a form element is empty.
	If it is display an alert box and focus
	on the element
*/
function isEmpty(formElement, message) {
	formElement.value = trim(formElement.value);
	
	_isEmpty = false;
	if (formElement.value == '') {
		_isEmpty = true;
		alert(message);
		formElement.focus();
	}
	
	return _isEmpty;
}

/*
	Set one value in combo box as the selected value
*/
function setSelect(listElement, listValue)
{
	for (i=0; i < listElement.options.length; i++) {
		if (listElement.options[i].value == listValue)	{
			listElement.selectedIndex = i;
		}
	}	
}