Simple Query Table Search Filter

Hit is a basic filter search for tables. It is currently filtering and searching the entire table (thead and tbody). Is there a way to make this script search by body only? I want to exclude thead from the filtered results and I tried adding "id =" kwd_search "" only instead of the tag, but it makes the script not function. Another one that I would like it not to do is scaling table rows when searching for results.

Any help is greatly appreciated and thanks for reading. Here is a live demo of what I have . I am very slow with this stuff, so it would be really nice for me if I could return a live example if it is not much.

// When document is ready: this gets fired before body onload <img src='http://blogs.digitss.com/wp-includes/images/smilies/icon_smile.gif' alt=':)' class='wp-smiley' /> 
$(document).ready(function(){
    // Write on keyup event of keyword input element
    $("#kwd_search").keyup(function(){
        // When value of the input is not blank
        if( $(this).val() != "")
        {
            // Show only matching TR, hide rest of them
            $("#my-table tbody>tr").hide();
            $("#my-table td:contains-ci('" + $(this).val() + "')").parent("tr").show();
        }
        else
        {
            // When there is no input or clean again, show everything back
            $("#my-table tbody>tr").show();
        }
    });
});
// jQuery expression for case-insensitive filter
$.extend($.expr[":"], 
{
    "contains-ci": function(elem, i, match, array) 
    {
        return (elem.textContent || elem.innerText || $(elem).text() || "").toLowerCase().indexOf((match[3] || "").toLowerCase()) >= 0;
    }
});