JS指定table的问题

Question

下面的JS已经指定了test 为什么,如果这个页面再加一个TABLE就出错了呢<table width="100%" border="0" cellpadding="1" cellspacing="1" id="test" > 
<script type="text/javascript">function setSum(obj){
    var sumTD = obj.parentNode.parentNode.getElementsByTagName("td")[6];
    if(!/^\d*$/.test(obj.value)){
        if(isNaN(parseInt(obj.value))){
            obj.value = "";
            sumTD.innerHTML = "";
        }else{
            obj.value = parseInt(obj.value);
        }
        return;
    }
    var price = parseFloat(obj.parentNode.parentNode.getElementsByTagName("input")[2].value),
        count = parseInt(obj.value),
        sum = price * count;    if (isNaN(sum)){
        sumTD.innerHTML = 0;
    }else{
        sumTD.innerHTML = sum;
    }
}function setAllSum(){
    var trs = document.getElementsByTagName("tr"),
        allSumTD = trs[trs.length-2].getElementsByTagName("td")[6],
        sum = 0;    for(var i=1;i<trs.length-2;i++){
        var curTD = trs[i].getElementsByTagName("td")[6];
        if(!isNaN(curTD.innerHTML)){
            sum += parseFloat(curTD.innerHTML);
        }
    }
    if (isNaN(sum)){
        allSumTD.innerHTML = "";
    }else{
        allSumTD.innerHTML = sum;
    }
}window.onload = function(){
    var trs = document.getElementsByTagName("tr");
    for(var i=1;i<trs.length-2;i++){
        setSum(trs[i].getElementsByTagName("input")[3]);
        setAllSum();
        trs[i].getElementsByTagName("input")[3].onkeyup = function(oEvent){
            setSum(this);
            setAllSum();
        }
    }
}
</script>

Answer 1

好象没有指定test哇var trs = document.getElementsByTagName("tr");//获得行
建议换成
var trs = document.getElementById("test").rows;