function checklogin()
		{
		if (document.chk.username.value=='')
		{alert('用户名不能为空');
		document.chk.username.focus();
		return false
		}
		if (document.chk.password.value=='')
		{alert('密码不能为空');
		document.chk.password.focus();
		return false
		}
}
function unselectall()
{
    if(document.all.chkAll.checked){
	document.all.chkAll.checked = document.all.chkAll.checked&0;
    } 	
}

function CheckAll(form)
{
  for (var i=0;i<form.elements.length;i++)
    {
    var e = form.elements[i];
    if (e.Name != "chkAll")
       e.checked = form.chkAll.checked;
    }
}

function check_s()
{
if (document.search.keyword.value=='')
{
alert('关键字不能为空');
document.search.keyword.focus();
return false
}
}
function resizepic(thispic) 
{ 
if(thispic.width>570) thispic.width=570; 
} 
function bbimg(o) 
{ 
  var zoom=parseInt(o.style.zoom, 10)||100; 
  zoom+=event.wheelDelta/12; 
  if (zoom>0) o.style.zoom=zoom+'%'; 
  return false; 
}