Is this random integer function acceptable for generating passwords?

I've been goofing around with random numbers a lot recently and have usually just used Math.Random as I've had no need to use something more secure, however I figured it would be useful to learn stuff like this and I was wondering how secure / practical this function is and some improvements I could implement.

function random_number(max) {
    let buffer=new ArrayBuffer(8);
    let ints=new Int8Array(buffer);
    window.crypto.getRandomValues(ints);
    ints[7]=64-1;
    ints[6]|=0xf0;
    let float=new DataView(buffer).getFloat64(0,true)-1;
    return Math.floor(float*Math.floor(max+1));
}