var pwOK = true;    
    var updateStrength = function(pw) {
		 alert("hier");
        pwOK = true;
        $('pwFail').hide();
        $('pwOK').hide();
        var post = 'pw='+escape(pw)+'&alias='+escape($('alias').value)+'&email='+escape($('email').value);
       
        new Ajax.Request('/password_check.php?ms='+new Date().getTime(), {
          method: 'post',
          postBody: post,
          encoding: 'ISO-8859-1',
          requestHeaders: {Accept: 'application/json'},
          onSuccess: function(transport) {
            var json = transport.responseText.evalJSON(true);
            setPwRuleStyle('rule1', json.rule1);
            setPwRuleStyle('rule2', json.rule2);
            setPwRuleStyle('rule3', json.rule3);
            setPwRuleStyle('rule4', json.rule4);
            setPwRuleStyle('rule5', json.rule5);
            if (pwOK) {
                $('pwOK').show();
            } else {
                $('pwFail').show();
            }
          }
        });
    }