js作用域

var a = 2, b = 3, c = 1;
        function test(a)
        {
            a = 1;
            var b = 2;
            c = 3;
        }
        test(10);
        alert(a);
        alert(b);
        alert(c);

答案是233

var a = 2, b = 3, c = 1;
function test(a)
{
a = 1;
var b = 2;
c = 3;
}
test(10);
alert(a);
alert(b);
alert(c);