Hi, this is not a question, actually it's a simple solution to get your table body vertically scrollable using purely css, tested only in Firefox 3.5.2, assuming correct Table DOM definitions (table, thead, tbody).
<style>
.someTBODYclassName {
height: 100px,
overflow-x: hidden,
overflow-y: visible
}
</style>
Of course this can be more tricky using jQuery or pure Javascript.
var maxHeightOfTBODY = your_calculations_here;
$("#TableId tbody.someTBODYclassName") //make it scrollable
.css({
"height": maxHeightOfTBODY+"px",
"overflow-x": "hidden",
"overflow-y": "visible",
"width": "100%"
});