Method 1:
function randomchars1(type, len) {
var radix = 10;
switch (type) {
case 3:
radix = 36;
break;
case 2:
radix = 16;
break;
}
len = len || 40;
var ar = new Uint8Array(len);
window.crypto.getRandomValues(ar);
var ret = [].map.call(ar, function (n) {
return n.toString(radix);
}).join("");
ret = ret.slice(0, len)
return ret;
}
Example 1: include 0-9
alert(randomchars1(1, 5));//44366
Example 2: include 0-9a-f
alert(randomchars1(2, 5));//f8a8a
Example 3: include 0-9a-z
alert(randomchars1(3, 5));//5s4p3
Method 2:
function randomchars2(type, len) {
var s = "0123456789";
switch (type) {
case 3:
s = "abcdefghijklmnopqrstuvwxyz0123456789";
break;
case 2:
s = "abcdef0123456789";
break;
case 4:
s = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
break;
}
return Array(len).join().split(',').map(function () {
return s.charAt(Math.floor(Math.random() * s.length));
}).join('');
}
Example 1: include 0-9
alert(randomchars2(1, 5));//43366
Example 2: include 0-9a-f
alert(randomchars2(2, 5));//b8a8a
Example 3: include 0-9a-z
alert(randomchars2(3, 5));//514p3
Example 4: include 0-9a-zA-Z
alert(randomchars2(4, 5));//5A4p3
