function checkForm()
{
	var xname, xemail, xliked, xsubject, xmessage;
	with(window.document.xactform)
	{
		xname    = sname;
		xemail   = email;
		xliked   = liked;
		xsubject = subject;
		xmessage = message;
	}
	
	if(trim(xname.value) == '')
	{
		alert('Please enter your name');
		xname.focus();
		return false;
	}
	else if(trim(xemail.value) == '')
	{
		alert('Please enter your email');
		xemail.focus();
		return false;
	}
	else if(!isEmail(trim(xemail.value)))
	{
		alert('Email address is not valid');
		xemail.focus();
		return false;
	}
	else if(trim(xsubject.value) == '')
	{
		alert('Please enter message subject');
		xsubject.focus();
		return false;
	}
	else if(trim(xmessage.value) == '')
	{
		alert('Please enter your message');
		xmessage.focus();
		return false;
	}
	else
	{
		xname.value    = trim(xname.value);
		xemail.value   = trim(xemail.value);
		xliked.value   = trim(xliked.value);
		xsubject.value = trim(xsubject.value);
		xmessage.value = trim(xmessage.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);
}