$(document).ready(function(){

	setInterval(phoneChanger, 5000);

});

function phoneChanger() {
	var newfile=0;
	oldfile = $('#telephonenumber').attr("src").substr(19,1);
	if (oldfile==1){newfile=2};
	if (oldfile==2){newfile=3};
	if (oldfile==3){newfile=1};
	fileToLoad = 'images/header_phone'+newfile+'.jpg';
	$('#telephonenumber').attr({src:fileToLoad});
}