I think this will work for you:
function makeid(length) {
var result="";
var characters="ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789";
var charactersLength = characters.length;
for ( var i = 0; i < length; i++ ) {
result += characters.charAt(Math.floor(Math.random() *
charactersLength));
}
return result;
}
console.log(makeid(5));