全选删除特效

<script language="JavaScript">

<!--

function CheckAll(chk) {

for (var i=0;i<chk.length;i++) chk[i].checked=true;

}

//-->

</script>

<input type="button" value="全" onclick="CheckAll(form.selAnnounce)"><input type='submit' value='删'>

````````````````这个是checkbox的name