Declaring Jquery object as variable?

Question

I am new to Jquery and javascript.

While I was writing a javascript code, I found myself using a particular jquery object often, so I declared a variable for it. For example,

$(document).ready(function() { var object_list = $("#object_list"); /*Do something with the variable*/ alert(object_list); object_list.hide(); });

However, this doesn't seem to work ("alert(object_list)" gives me a null value).

Is declaring a variable like this wrong in jquery???

If so, then what is the right way so that I can refer to commonly used Jquery object??\

Thanks!

A null value? Did you somehow overwrite $, for example by loading Prototype.js? — Bergi
– Bergi, Commented Aug 17, 2013 at 13:03
@Bergi I join my voice to you, the alert should show an Object even if the selector doesn't much anything, so yes, good point, $() here is not an alias to jQuery(). — Nabil Kadimi
– Nabil Kadimi, Commented Aug 17, 2013 at 13:09
@NabilKadimi as a matter of fact, it should return an Array, empty or containing one or more HtmlElement objects. — KooiInc
– KooiInc, Commented Aug 17, 2013 at 13:19
@KooiInc - I would say it's an empty jQuery object - jsfiddle.net/nabil_kadimi/YVYWP/4 — Nabil Kadimi
– Nabil Kadimi, Commented Aug 17, 2013 at 13:26

Nabil Kadimi · Accepted Answer · 2014-07-05 01:16:17Z

Your jQuery is probably working in noConflict mode, which means that you detached the alias $ = jQuery somewhere earlier in your code. WordPress for example does that (see latest line of wp-includes/js/jquery.js).

Use this code instead:

jQuery(document).ready(function($) { var object_list = $("#object_list"); /*Do something with the variable*/ alert(object_list); object_list.hide(); });

What you are doing is aliasing the jQuery object within the .ready method, see the section for Aliasing the jQuery Namespace in the .ready() method documentation.

Khanh TO · Accepted Answer · 2013-08-17 13:26:39Z

You could wrap your code inside an immediate function to avoid naming collision with $. This technique is useful when you already have a lot of code using the $ and refactoring to change the name may be error-prone.

(function($){ $(document).ready(function() { var object_list = $("#object_list"); /*Do something with the variable*/ alert(object_list); object_list.hide(); }); })(jQuery);

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