var f =function(x) {
console.log(x);
console.log(arguments[0])
console.log(‘-------------before delete-------------‘)
x = 3;
// arguments[0] = 3;
// delete arguments[0];
delete x;
console.log(x);
console.log(arguments[0])
}
f(2);
原文：http://www.cnblogs.com/ax-null/p/6951727.html