function SF_selectAll(obj)
{
	var Cb = obj.getElementsByTagName("input");
	for( var i=0; i<Cb.length; i++) 
	{
		if(Cb[i].type=="checkbox" && Cb[i].value != "")
		{
			Cb[i].checked = true;
		}
	}
}

function SF_selectNo(obj)
{
	var Cb = obj.getElementsByTagName("input");
	for( var i=0; i<Cb.length; i++) 
	{
		if(Cb[i].type=="checkbox" && Cb[i].value != "")
		{
			Cb[i].checked = !Cb[i].checked;
		}
	}
}

function ranArray(n)
{
        var a,r,l=n.length,x,d=new Array(l);
        for(x=l-1;x>=0;x--)
        {
                r=Math.floor(Math.random()*(x+1));
                d[x]=n[r];
                n[r]=n[x];
        }
        return d;
}
function SelectRandAll(form){
	var k=[];
	for(var i=0;i<form.checked.length;i++){
		var e = form.checked[i];
		e.checked = false;
		k[i]=i;
	}
	var newform=ranArray(k);
	var l=[];
	for (var i=0;i<newform.length && i<20;i++){
		l[i]=newform[i];
		var e = form.checked[newform[i]];
		e.checked = true;
	}
//alert(form.checked.length);
}

function SF_Listenclass(obj)
{
	var Cb = obj.getElementsByTagName("input");
	var Id="";
	var Count=0;
	for( var i=0; i<Cb.length; i++) 
	{
		if(Cb[i].type=="checkbox")
		{
			if(Cb[i].checked)
			{
				Id += Cb[i].value + ","
				Count++
			}
		}
	}
	if (Count == 0)
	{
		alert("请选择曲目!");
		return;
	}
	if (Count > 100){
		alert("一次最多收听100首曲目!")
		return;
	}
	window.open('/play.htm?d=' + escape(Id) ,'letsmusicplayer');
}