function test0 (){
for (var i = 0; i < 5; i++) {
setTimeout(function(){
console.log(new Date(),"test 0 " + i)
}, 0)
}
console.log(new Date,i)
}
test0();
// 改成 let
function test1 (){
for (let i = 0; i < 5; i++) {
setTimeout(function(){
console.log(new Date(),"test 1 " + i)
}, 0)
}
// console.log(new Date,i) //i is not defined
}
test1();
//立即执行函数
function test2 (){
for (var i = 0; i < 5; i++) {
(function(){
// setTimeout(function(i){
console.log(new Date(),"test 2 "+i)
// }, 0)
})(i)
}
// console.log(new Date,i) //i is not defined
}
test2();