function trim(cText) {
	while (cText.substring(0,1) == ' ') { cText = cText.substring(1,cText.length); }
	while (cText.substring(cText.length-1,cText.length) == ' ') { cText = cText.substring(0,cText.length-1); }
	return cText;
}
function emailCheck(f) {
	var filter=/^.+@.+\..{2,4}$/;
	var em = trim(f.youremail.value);
	var sj = trim(f.subject.value);
	var bd = trim(f.content.value);
	var pc = trim(f.postcode.value);
	
	if (em.length == 0) {
		alert('Please enter an email address');
		return false;
	} else if (!filter.test(em)) {
		alert('Please enter a valid email address');
		return false;
	} else if (sj.length == 0) {
		alert('Please enter a subject');
		return false;
	} else if (bd.length == 0) {
		alert('Please enter a message');
		return false;
	} else if (pc.length == 0) {
		alert('Please enter your postcode');
		return false;
	} 
	
		
	return true;
}