Пример, для наглядности.
html:
<div id="test1">123</div>
html, css:
<div id="test2">123</div>
<style type="text/css">#test2 {color:#a00}</style>
html, css, js:
<div id="test3">123</div>
<style type="text/css">#test3 {color:#a00}</style>
<script type="text/javascript">
var tst=document.getElementById('test3');
setInterval(function(){tst.style.paddingLeft=Math.floor(Math.random()*100)+'px'},100)
</script>