Why "this" is not working?

Question

In java script when we make a new constructor function we use "this.property name". We use "this" to refer the object which currently in use. But in a general function we doesn't use "this" keyword. According to my understanding if we use "this" in function it should point to the current function. However when we used, it was not producing the expected result. Why? Example

function greet(name){ console.log("Hello " + this.name); }

Output is "Hello" then blank.

call any function with `new` keyword, and `this` inside the function will refer to a newly constructed object — Igor, Feb 23 '17 at 04:28
where is your code snippet so we can batter to help in right direction @PiyaliGhosh — Divyesh Kanzariya, Feb 23 '17 at 04:33
I have added my code above. Please look into it. @DivyeshKanzariya — Piyali Ghosh, Feb 23 '17 at 04:38

score 0 · Answer 1 · answered Feb 23 '17 at 04:31

0

Read this about this

In most cases, the value of this is determined by how a function is called.

answered Feb 23 '17 at 04:31

Amol Katdare

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score 0 · Accepted Answer · answered Feb 23 '17 at 04:31

0

Because in general function, we are by default referring 'window' object so anything we make it becomes window level object or variable.

Like,

function fun(){
 this.title = "window";
}

fun();

or window.fun(); //both are same. Since we call window.fun, this.title means window.fun.

If you create like this:

var obj = { }

**Now to make title at obj level, you can do like this:

fun.call(obj);

Now you can call obj.title.**

answered Feb 23 '17 at 04:31

Nitesh

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Thanks. I changed my this to window.this. Now it is working fine. – Piyali Ghosh Feb 23 '17 at 04:43
@Igor, Sorry I don't understand your comment. – Piyali Ghosh Feb 23 '17 at 04:52

score 0 · Answer 3 · answered Feb 23 '17 at 04:32

When you use the new keyword in javascript an implicit object is created and returned from the function call. Inside of the function this refers to the newly created object. Calling a function without new does not have the same behavior.

See: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/new

Why "this" is not working?

3 Answers3