Autogenerate Password (random string)

Hello,

When opening a document, I would like to automatically fill a text field with random text (password generator).
Unfortunately I don't find much about it and my approach seems completely wrong 😞

I hope someone can help me out here 🙂

Here is my code:

function start_kundenkennwort_gen() {

//var randomstring = this.getField("kd_kundenkennwort");

var chars = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXTZabcdefghiklmnopqrstuvwxyz";
var string_length = 8;
var randomstring = '';
for (var i=0; i<string_length; i++) {
var rnum = Math.floor(Math.random() * chars.length);
randomstring += chars.substring(rnum,rnum+1);
}

document.randform.kd_kundenkennwort.value = randomstring;
}