$$('a').setEach('href', function(currentHref, i){
    return currentHref + '?foo=bar';
});

function replaceFooWithBar(string){
    return String(string).replace(/\bfoo\b/g,'bar');
};

$$('a').setEach('html',[
    "New foo HTML!",
    function(html){ return html + ' appended moar foo!'; },
    replaceFooWithBar,
    function(html,i){ return html + ' Index is ' + i; }

]);


$$('a').setEachStyle({
    'color': function(currentColor, i) {
        i = i.toString(16);
        return ['#', i, i, i].join('');
    },
    'background-color': function(currentColor, i) {
        i = (15 - i).toString(16);
        return['#', i, i, i].join('');
    }
});

<a href="0.html">0</a>
<a href="1.html">1</a>
<a href="2.html">2</a>
<a href="3.html">3</a>
<a href="4.html">4</a>
<a href="5.html">5</a>
<a href="6.html">6</a>
<a href="7.html">7</a>
<a href="8.html">8</a>
<a href="9.html">9</a>
<a href="10.html">10</a>
<a href="11.html">11</a>
<a href="12.html">12</a>
<a href="13.html">13</a>
<a href="14.html">14</a>
<a href="15.html">15</a>

MooShell