function VerifyMobile() {
	if ( document.getElementById('Mobile') ) {
		MobileNo = document.getElementById('Mobile').value;
		
		//replace non-integers with nothing
		Finder = new RegExp( "[^0-9]+", "g" );
		MobileNo = MobileNo.replace( Finder, '' );
		document.getElementById('Mobile').value = MobileNo;
		
		//check mobile number entered is 11 chars long
		var MobileNoLength = MobileNo.length;
		//check Mobile number prefix ibegins with 07		
		Prefix = MobileNo.substring( 0 , 2 );

		if ( MobileNoLength != 11 || Prefix != '07' ) {
			alert('The mobile phone number you have entered is not valid');
			return false;
		}
	}

	return true;
}

function Init() {
	var Form2Submit = document.getElementById('subscribeForm');
	if ( Form2Submit ) {
		Form2Submit.onsubmit = function() {
			return VerifyMobile();
		}
	}
}

window.onload = Init;