Skip to content

Latest commit

 

History

History
70 lines (53 loc) · 1.27 KB

作用域小练习.md

File metadata and controls

70 lines (53 loc) · 1.27 KB
var a = 123;
function fun(){
   alert(a);
}
fun();

=> 123


var a = 123;
function fun(){
   alert(a);
   var a = 456;
}
fun();
alert(a);

=>  undefined 123 


var a = 123;
function fun(){
   alert(a);
   a = 456;
}
fun();
alert(a);

=> 123 456  


var a = 123;
function fun(a){
   alert(a);
   a = 456;
}
fun();
alert(a);

=> undefined 123 


var a = 123;
function fun(a){
   alert(a);
   a = 456;
}
fun(123);
alert(a);

=> 123 123