<input type=button value="Add" onclick='additem("tb")'>
<table id="tb" border="1"></table>
<script language="javascript">
function additem(id){
    var row,cell,str;
    row = eval("document.all["+'"'+id+'"'+"]").insertRow();
    if(row != null ){
        cell = row.insertCell();
        str="<input type="+'"'+"file"+'"'+" name="+'"'+"addfile"+'"'+">项目<input type="+'"'+"text"+'"'+" name="+'"'+"v_item"+'"'+"><input type="+'"'+"button"+'"'+" value="+'"'+"delete"+'"'+" onclick='deleteitem(this,"+'"'+"tb"+'"'+");'>"
        cell.innerHTML=str;
    }
}
function deleteitem(obj,id){
    var rowNum,curRow;
    curRow = obj.parentNode.parentNode;
    rowNum = eval("document.all."+id).rows.length - 1;
    eval("document.all["+'"'+id+'"'+"]").deleteRow(curRow.rowIndex);
}
</script>