Self-calling unnamed function in the JavaScript. Where is it used? Used in Yandex advertising. Example: ( function(){ ... } )();

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Self-calling unnamed function in the JavaScript. Where is it used? Used in Yandex advertising. Example: ( function(){ ... } )(); | standard ES5

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Self-calling unnamed function in the JavaScript | standard ES5

last updated: 1 Augusta 2020

A self-calling unnamed function is convenient because it does not have a name and you can write many such functions in one file and there will be no conflicts with names.

Syntax without parameters
( function(){} )();

or

( function(){}() );

Syntax with parameters
( function (param1, param2, ...){} )(meaning1, meaning2, ...);

Example

Self-calling unnamed function
no parameters

JavaScript

( function(){ /* your code here ... */ } )();

Self-calling unnamed function
with parameters

JavaScript

( function(){ /* your code here ... */ } )();

Example

Html

<html>
<body>

<script>

     // Self-calling unnamed function with no parameters
     ( function(){ alert('Hello1'); } )();

     // Self-calling unnamed function with no parameters
     ( function(){ alert('Hello2'); }() );

     // Self-calling unnamed function with one parameter
     ( function(text) {alert(text);} )("Hello3");

</script>

</body>
</html>

on the screen we will see:
"Hello1"
"Hello2"
"Hello3"

Where is the self-calling unnamed function used?

In order not to write a new function with a name, but to call a self-calling unnamed function and not be a conflict with the names of other functions. [konec_stroki]That is, usually a self-calling unnamed function is some independent function of its own that does something.

An example of using a self-calling unnamed function:

Self-calling unnamed function used in advertising Yandex
If you want your website to make money then you Yandex offers to embed ads on your page.
Yandex for each site gives its own piece of advertising code. Here's an example of such ad code:

JavaScript

<div id="yandex_rtb_R-A-234410-1"></div>
<script type="text/javascript">
     (function(w, d, n, s, t) {
          w[n] = w[n] || [];
          w[n].push(function() {
               Ya.Context.AdvManager.render({
                    blockId: "R-A-234410-1",
                    renderTo: "yandex_rtb_R-A-234410-1",
                    horizontalAlign: false,
                    async: true
               });
          });
          t = d.getElementsByTagName("script")[0];
          s = d.createElement("script");
          s.type = "text/javascript";
          s.src = "//an.yandex.ru/system/context.js";
          s.async = true;
          t.parentNode.insertBefore(s, t);
     })(this, this.document, "yandexContextAsyncCallbacks");
</script>

(function(w, d, n, s, t) ... this is the self-calling unnamed function.
That is, your page can have a lot of your functions. [konec_stroki] Calling a self-calling unnamed function will not call any of your functions (there will be no name conflict).

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Unnamed function in the JavaScript . Using an unnamed function: pass an unnamed function as a parameter to another function. Example: Calculate(15, 7, function(v1, v2) {return v1+v2;}); | standard ES5

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Create a file js with an object containing export variables and functions. This is an example of using a self-calling unnamed function | standard ES5