js正则验证表单密码强度

<script language="JavaScript">
function EvaluatePassword(word)
{
    if (word == "")
    {
        return 0;
    }
    else if (word.length < 6)
    {
        return 1;
    }
    else
    {
        return word.match(/[a-z](?![^a-z]*[a-z])|[A-Z](?![^A-Z]*[A-Z])|d(?![^d]*d)|[^a-zA-Zd](?![a-zA-Zd]*[^a-zA-Zd])/g).length;
    }
}
var test = new Array("", "a1_", "abcdef", "abcde123", "ads23%", "aA1B2^&2");
for(var i in test)
{
    document.write(test[i] + " 的密码强度为" + EvaluatePassword(test[i]) + "<br>");
}
</script>