Javascript random password

// generate random password
function randomPassword()
{
var chars = "ABCDEFGHIJKLMNOPQRSTUVWXTZabcdefghiklmnopqrstuvwxyz";
var string_length = 8;
var randomstring = '';
var charCount = 0;
var numCount = 0;

for (var i=0; i < string_length; i++)
{
// If random bit is 0, there are less than 3 digits already saved, and there are not already 5 characters saved, generate a numeric value.
if((Math.floor(Math.random() * 2) === 0) && numCount < 3 || charCount >= 5)
{
randomstring += Math.floor(Math.random() * 10);
numCount += 1;
}
else
{
// If any of the above criteria fail, go ahead and generate an alpha character from the chars string
var rnum = Math.floor(Math.random() * chars.length);
randomstring += chars.substring(rnum,rnum+1);
charCount += 1;
}
}

return randomstring;
}