Why would a JavaScript variable start with a dollar sign?

javascript naming-conventions
Ken picture Ken · Oct 15, 2008 · Viewed 242.7k times · Source

I quite often see JavaScript with variables that start with a dollar sign. When/why would you choose to prefix a variable in this way?

(I'm not asking about $('p.foo') syntax that you see in jQuery and others, but normal variables like $name and $order)

Answer

jonstjohn picture jonstjohn · Feb 16, 2009

Very common use in jQuery is to distinguish jQuery objects stored in variables from other variables.

For example, I would define:

var $email = $("#email"); // refers to the jQuery object representation of the dom object
var email_field = $("#email").get(0); // refers to the dom object itself

I find this to be very helpful in writing jQuery code and makes it easy to see jQuery objects which have a different set of properties.

Related questions

Can someone explain the dollar sign in Javascript?

The code in question is here: var $item = $(this).parent().parent().find('input'); What is the purpose of the dollar sign in the variable name, why not just exclude it?

Read More
Underscore prefix for property and method names in JavaScript

Is the underscore prefix in JavaScript only a convention, like for example in Python private class methods are? From the 2.7 Python documentation: “Private” instance variables that cannot be accessed except from inside an object don’t exist in Python. However, …

Read More
What is the javascript filename naming convention?

Should files be named something-with-hyphens.js, camelCased.js, or something else? I didn't find the answer to this question here.

Read More