Large random number
Make a large random number by putting several random numbers together in a string.
HTML
<div id="demo"></div>
JavaScript
var s = '';
for (var i = 0; i < 10; i++) {
s += Math.floor(Math.random() * 1e10);
}
while (s.length > 1 && s[0] == '0') s = s.substr(1);
document.getElementById('demo').innerHTML = s;