<html>
<head>
<script>
function myFun()
{
var ckb = document.getElementById("ckb");
var table = document.getElementById("table");
var tBody = table.childNodes[0];
for ( var i=0 ;i<tBody.childNodes.length;i++)
{
var row = tBody.childNodes[i];
var cell = row.childNodes[0];// 表格第一个单元格放置checkbox
if ( cell.childNodes[0].getAttribute ("type")=="checkbox")
{
cell.childNodes[0].checked = ckb.checked;
}