/* Called to validate the page before submission*/
function validatePage(f){
	// Strip whitespace and place into variables
	name				= stripWhitespace(f.name.value);
	email				= stripWhitespace(f.email.value);
	telephone			= stripWhitespace(f.telephone.value);
	message				= stripWhitespace(f.message.value);
	
	
	// Check required fields have information
	if(name.length == 0)						{ alert('Please tell us your name'); f.name.focus(); return false; }
	if(email.length == 0)						{ alert('Please enter your email address'); f.email.focus(); return false; }
	if(!validateEmail(email))				{ alert('This email address does not appear to be valid, please check it'); f.email.focus(); return false; }
	if(telephone.length == 0)				{ alert('Please enter your phone number'); f.telephone.focus(); return false; }
	if(!validateTelephone(telephone)) 		{ alert('This telephone number is not valid, please check and try again'); f.telephone.focus(); return false; }
	if(message.length == 0)						{ alert('Please leave us a message'); f.message.focus(); return false; }
	
	
	
	// If all ok then return true (validation passed)
	return true;
}

/* Remove white space from start & end of string */
function stripWhitespace(str) {
	str = this != window ? this : str;
	return str.replace(/^\s+/g, '').replace(/\s+$/g, '');
}

/* Function to validate an email address */
function validateEmail(email) {
  var regex = /^[a-zA-Z0-9._-]+@([a-zA-Z0-9.-]+\.)+[a-zA-Z0-9.-]{2,4}$/;
  return regex.test(email);
}

/* Function to validate Telephone number, ie 11-13 digits */
function validateTelephone(telephone) {
telephone = telephone.replace (/[^\d]/g,'');
var regex = /^\d{11,13}/;
return regex.test(telephone);
}