CODEWITHSUNDEEP
javascript
Maizere Pathak
Maizere Pathak

Reputation: 299

javascript alert method

Why is the following line not alerted?

  <script>
  alert(x);//this line is not executed or alerted  ???.It should have alerted "undefined" 
  console.log(x)//reference error 
  var y="maizere";
  alert(y);//this line is also not executed or alerted  ???

  </script>

Any undeclared variables are treated as global variable in javascript right?

Upvotes: 0

Views: 322

Answers (3)

Kami
Kami

Reputation: 19457

You are getting undefined and undeclared confused.

The variable x is undeclared - it has not been declared in code yet, so

alert(x);

will raise an error in the likes of 'x' is not declared.

Your code should read

<script>
  var x;
  alert(x);//this line is not executed or alerted  ???.It should have alerted "undefined" 
  var y="maizere";
  alert(y);//this line is also not executed or alerted  ???
</script>

Upvotes: 2

Kos
Kos

Reputation: 72319

alert(x);//this line is not executed or alerted  ???.It should have alerted "undefined"

That's incorrect. This line raises a ReferenceError because there's no variable x.

Contrast this with situation:

var obj = {};
alert(obj.x); // undefined - there's no attribute x

Upvotes: 2

Adrian Marinica
Adrian Marinica

Reputation: 2201

Whatever you put inside an alert call should be defined. If it is not (your case) then an error is thrown. So, you should define the variable first. For the errors, you should check a JavaScript (browser) console.

var x = "Test";
alert(x); // shows
var y = 123;
alert(y); // y also shows, because there is no error thrown inside the alert for x

Upvotes: 0

Related Questions