[javascript] generate random string for div id

i like this simple one:

function randstr(prefix)
{
    return Math.random().toString(36).replace('0.',prefix || '');
}

since id should (though not must) start with a letter, i'd use it like this:

let div_id = randstr('youtube_div_');

some example values:

youtube_div_4vvbgs01076
youtube_div_1rofi36hslx
youtube_div_i62wtpptnpo
youtube_div_rl4fc05xahs
youtube_div_jb9bu85go7
youtube_div_etmk8u7a3r9
youtube_div_7jrzty7x4ft
youtube_div_f41t3hxrxy
youtube_div_8822fmp5sc8
youtube_div_bv3a3flv425