Circle All The ChildNodes

I wanna get all the text nodes of the children of an element. The goal is to get an array with all the textNodes in each cell of a table, without any other nodes that might ocure whithin that cell (<p>, <br> etc...)

I mean if:
<td>12</td>
<td>1<p>23<b>34</b>5</p>6</td>
I need:
var txt = new Array()
txt[0] = &#3912;'
txt[1] = ?'

Now I had to circle through all the childNodes to extract all the text nodes. I have build a function, but something is wrong in the code, and I don't sense what. I need soime fresh eyes, any ideeas? Where's the mistake?:

<script type="text/javascript">
function checkCell(){
var allC = document.getElementById('tab').getElementsByTagName('td');//cells' collection
var txt = new Array()
for(var i=0;i<allC.length;i++){
txt[i]=''
while(allC[i].hasChildNodes()){
var chC = allC[i].childNodes;
for(var j=0;j<chC.length;j++){
if(chC[j].nodeType==3){
txt[i]+=chC[j].data;
}
}
allC[i]=allC[i].childNodes;
}
}
alert(txt[1])
}
onload=checkCell;
</script>