count of specific letters

[johnjohn2]

Is there a way to use javascript to count all the letter "d" in a specific table? I have a table of information on my page and I need some way of counting specific letters in the information.

So the out put would be something like d=2

[muazzez]

 
<script type="text/javascript">

function find(){
var  el = document.getElementById('tableid');
el = el.getElementsByTagName('td');
var  td, i = 0, str ="";

while(td = el[i++]) {
str += td.innerHTML;
} 
alert(str);
var c = "d";
var n = str.match(RegExp('('+c+')','g')).length;
alert(n);  // 6
}
</script>
<input type="button" onclick="find()">
<table id="tableid">
<tr><td>abcdef</td><td>abcdef</td><td>abcdef</td></tr>
<tr><td>abcdef</td><td>abcdef</td><td>abcdef</td></tr>
</table>