The problem of Date() of js under IOS system

The following code returns NaN in the IOS safari browser, but is normal in the Android browser:
var datetime = '2017-12-25 11:02:27';
var time = new Date(datetime );
console.log("Print : " + time);
Return result: NaN

replace - with /:

var datetime = '2017/12/25 11:02:27';