Если брать две таблицы, что бы их раскрашивало по одной функции, то вот рабочий пример.
<html>
<head>
<link rel="stylesheet" href="style.css" type="text/css" />
<script type="text/javascript" src="prototype.js"></script>
<script type="text/javascript">
$(document).observe('dom:loaded', function(){
var arr_class = ['range1','range2','range3'];
var abc_class = ['a', 'b', 'c'];
function table_colorize(elements, array_class)
{
elements.each(function(i, j){
var num = i.innerText || i.textContent;
var $class;
if($R(1,30).include(num))
$class = array_class[0];
if($R(40,60).include(num))
$class = array_class[1];
if($R(70,90).include(num))
$class = array_class[2];
i.addClassName($class);
});
};
var first = $$('table#first td');
var second = $$('table#second td');
table_colorize(first, arr_class);
table_colorize(second, abc_class);
});
</script>
</head>
<body>
<table id="obsh">
<tr>
<td>
<table id="first">
<tr>
<td>0.7</td>
<td>2.1</td>
<td>3.7</td>
</tr>
<tr>
<td>4.6</td>
<td>5.5</td>
<td>6.1</td>
</tr>
<tr>
<td>7.4</td>
<td>8.3</td>
<td>9.4</td>
</tr>
</table>
</td>
<td>
<table id="second">
<tr>
<td>10</td>
<td>20</td>
<td>30</td>
</tr>
<tr>
<td>40</td>
<td>50</td>
<td>60</td>
</tr>
<tr>
<td>70</td>
<td>80</td>
<td>90</td>
</tr>
</table>
</td></tr>
</table>
</body>
</html>