var MrFlySand = "A";
MrFlySand.charCodeAt();// 65
var FlySand= ‘a‘;
FlySand.charCodeAt();// 97
var MrFlySand = 97;
String.fromCharCode(MrFlySand); // ‘a‘
var FlySand = 100;
String.fromCharCode(FlySand); // ‘d‘
原文：https://www.cnblogs.com/MrFlySand/p/14861977.html