解决ios设备中angularjs无法改变页面title的问题

$rootScope.$watch('title',function(title){
var body = document.getElementsByTagName('body')[0];
document.title = title;
var iframe = document.createElement("iframe");
iframe.title = '';
iframe.width = 0;
iframe.height = 0;
iframe.setAttribute("src", "/empty.png");

iframe.addEventListener('load', function() {
setTimeout(function() {
iframe.removeEventListener('load');
document.body.removeChild(iframe);
}, 0);
});
document.body.appendChild(iframe);