setTimeout(function(){
console.log(a);
},0)//异步 

var a=10;
console.log(b);//undefault 1
console.log(fn);//function fn(){
//setTimeout(function(){
//console.log('setTimeout 10ms'); 
//},10)
//}
var b=20;

function fn(){
setTimeout(function(){
console.log('setTimeout 10ms');
},10)
}//异步 

fn.toString=function(){
return 30;
}//表达式

console.log(fn);//30

setTimeout(function(){
console.log("setTimeout 20ms")
},20);//

fn();

function fnu() {
// body...
var set = 10;
}
console.log(fnu);
fnu.hs = function() {
// body...
return 40;
}
console.log(fnu);