Javascript $ notation

Question

Please can anyone explain what this javascript code exactly does.

$('#element_id').html(response.title);

I need to access the value of the element_id but I can't using document.getElementById.

Thanks

http://stackoverflow.com/questions/846585/can-someone-explain-the-dollar-sign-in-javascript — Hashem Qolami, Jun 29 '13 at 14:32
`"but I can't using document.getElementById"` - Why can't you? `document.getElementById` should get the element with the given ID. — David, Jun 29 '13 at 14:32
what sort of element is this? a span, a text input box, a dropdown (which has a text and a value and a selected index). .val() gets many values, but value doesn't mean the same thing in all contexts. — MatthewMartin, Jun 29 '13 at 14:35
[What is the XY Problem](http://meta.stackexchange.com/questions/66377/what-is-the-xy-problem) — , Jun 29 '13 at 14:38
Please ask about your actual problem. It seems you've deviated from your issue onto something tangentially related at best. — , Jun 29 '13 at 14:47

score 2 · Answer 1 · answered Jun 29 '13 at 14:31

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This code just calls a function named $ and access a method of the returned object.

It's probably jQuery code due to the selector string.

$('#element_id'): Returns a jQuery object for the element with the given ID.
.html(response.title): Sets the inner HTML of the DOM element to response.title.

The raw JavaScript would look like this:

document.getElementById("element_id").innerHTML = response.title;

answered Jun 29 '13 at 14:31

ComFreek

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Thanks a lot ComFreek. Now I understand the code. I would never have guessed $ as a function name though. – Masood Hosseini Jun 30 '13 at 06:29

score 1 · Answer 2 · answered Jun 29 '13 at 14:31

1

This code uses probably JQuery. The $ is the basic function defined by JQuery. You can call it to get access to element using a special query language defined by JQuery.

answered Jun 29 '13 at 14:31

LaurentG

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score 1 · Answer 3 · edited Jun 29 '13 at 14:36

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$ probably refers to jQuery, one of the most frquently used JS libraries.

What this snippet basically does is setting the HTML content of the element with the id element_id to the title attribute of the response object.

edited Jun 29 '13 at 14:36

ComFreek

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answered Jun 29 '13 at 14:32

luk2302

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$ might refers to anything except jQuery **plugin**. – Hashem Qolami Jun 29 '13 at 14:33
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jQuery is not a plugin, it's just a library of JS utility functions. Furthermore, `$` can be set to anything. It does not need to be jQuery. (I am not the one who has downvoted). – ComFreek Jun 29 '13 at 14:34
you can be SURE it is jQuery, no need t downvote for this. And you are right, jQuery is a library which can be extended using plugins. – luk2302 Jun 29 '13 at 14:35
the question has been added an jquery tag, so it IS jquery. – luk2302 Jun 29 '13 at 14:37
@luk2302 why can you be sure it is jQuery? – t.niese Jun 29 '13 at 14:38
@luk2302 It wasn't the original OP, it was MatthewMartin (see revision log). But yes, it's probably jQuery ;) +1 from me. – ComFreek Jun 29 '13 at 14:39
i know, it wasn´t jQuery from the beginning, but i´d say 99% ;) – luk2302 Jun 29 '13 at 14:40
@luk2302, please update yor answer, using the `might be`, `could be` `probably` keywords is more appropriate to refers $ to a specific JS Object. – Hashem Qolami Jun 29 '13 at 14:40
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@luk2302 Sorry, I'm in `"use strict"` mode ;) – Hashem Qolami Jun 29 '13 at 14:46

score 1 · Answer 4 · answered Jun 29 '13 at 14:35

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It looks like jQuery, which is a Javascript library. The $('#element_id') creates a jQuery object for the element with the id element_id in the DOM. Then .html(response.title) will put the value of response.title as HTML inside the element.

answered Jun 29 '13 at 14:35

gitaarik

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Javascript $ notation

4 Answers4