random pick item from array

function randomPick(list){
    return list[ Math.random()*list.length|0 ];
}

function test(listSize,testCount){
	listSize = listSize||20;
	testCount = testCount||100;
	var list=[ ];
	for (var i=0;i<20;i++){
		list.push("a_"+i);
	}

	var rs=[]
	for (var i=0;i<100;i++){
		rs.push(randomPick(list));
	}
	rs.sort();
	for (var i=0;i<rs.length;i++){
		console.log(rs[i]);
	}
}

test();