why add this $(function () { at the first line of the javascript file?

Question

$(function () {
 console.log('hello');
 //...
})

I saw the code like this. Don't know the purpose of adding the first line (function)? Could Someone explain this?

Please search before you ask. https://stackoverflow.com/questions/1140089/why-do-you-need-to-invoke-an-anonymous-function-on-the-same-line — Ahmet Can Güven, Aug 01 '17 at 06:23
Official docs : https://learn.jquery.com/using-jquery-core/document-ready/ — Junior Dussouillez, Aug 01 '17 at 06:23
Possible duplicate of [How do JavaScript closures work?](https://stackoverflow.com/questions/111102/how-do-javascript-closures-work) — Suresh Atta, Aug 01 '17 at 06:30

score 1 · Answer 1 · answered Aug 01 '17 at 06:23

1

That is just jQuery short-hand for

$(document).ready(function() { ... });

answered Aug 01 '17 at 06:23

varman

It's *probably* jQuery, but it could be some other library too. – RobG Aug 01 '17 at 06:31

Koby Douek · Accepted Answer · 2017-08-01T06:30:58.303

1

Wrapping you Javascript code with $(function () {:

$(function () {
    console.log( "ready!" );
});

is the same (a Shorthand version) as writing:

$(document).ready(function() {
    console.log( "ready!" );
});

Which ensures the script will only run once the page Document Object Model (DOM) is ready for Javascript code to execute (Jquery docs).

edited Aug 01 '17 at 06:30

answered Aug 01 '17 at 06:23

Koby Douek

2 Answers2