function CheckOthers(form)
{
	for (var i=0;i<form.elements.length;i++)
	{
		var e = form.elements[i];
//		if (e.name != 'chkall')
			if (e.checked==false)
			{
				e.checked = true;// form.chkall.checked;
			}
			else
			{
				e.checked = false;
			}
	}
}

function CheckAll(form)
{
	for (var i=0;i<form.elements.length;i++)
	{
		var e = form.elements[i];
//		if (e.name != 'chkall')
			e.checked = true// form.chkall.checked;
	}
}

function ChkChecked(f){//f为form   
          var   a  = f.elements;   
          for   (var   i=0;   i<a.length;   i++){   
               if(a[i].type=="checkbox"   &&   a[i].checked)   
		return   true;   
          }   
          alert("请至少选择一首歌曲进行播放!");   
          return false;   
  }