/*一.变量作用域一道小题*/
var x='a';
function printX(){
console.log(x);
var x='b';
console.log(x);
}
printX();
var y='c';
function printY(){
console.log(y);
y='d';
console.log(y);
}
printY();
//输出结果undefined,b,c,d
/*二.输出结果*/
//alert(null instanceof Object);
//alert(null == undefined);//true
//alert(NaN == NaN);
//alert(false == undefined);
/*三.考察局部变量*/
function foo(a){
var a;
return a;
}
function bar(a){
var a="bye";
return a;
}
alert([foo('hello'),bar('hello')]);//hello,bye
