// 加密
function encryption(str) {
let newstr = [];
let number = Math.random()*200; // 0 ~ 接近200
number = Math.trunc(number) // 0 ~ 199
for (let i = 0; i < str.length; i++) {
newstr.push(str.charCodeAt(i) + number);
}
newstr.push(number)
return escape(newstr.toString());
}

// 解密
function decrypt(str) {
str = unescape(str);
// 把字符串以逗号切割为数组
let arr = str.split(‘,’);
let number = arr.pop();
let newarr = [];
arr.forEach(function (item) {
let temp = String.fromCharCode(item – number);
newarr.push(temp)
});
return newarr.join(”);
}