javascript中的name关键字是什么？

Question

I am a beginner in javascript , I was trying to play with variables until i reached to this issue, when i have a variable called name , and i commented its definition step , it still has the same value , although i commented it . and this happens only with keyword "name" , so what is it ?

<script>
   // var name="mina"; i commented it now , so if you want to test , enable it once , and then comment it , it will still give you the result although i commented it and deleted the cache
  //  var name;
alert(name);
</script>

Answer 1

name is not a reserved word in Javascript. As the sample code is not executing within any specific scope (within a function ect.) the name variable is referencing window.name .

console.log(name);
// output: "" (window.name)

(function(){
 console.log(name);
})()
// output: undefined

See https://developer.mozilla.org/en/docs/Web/API/Window/name for more details.

Answer 2

The variable is not in a function, so it's a global variable. Global variables are added to the window and it stays there (until you refresh the page if I recall correctly).

You don't reset the variable so it will keep having the same value.