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JavaScript jQuery Basics (2014) Creating a Simple Lightbox Perform: Part 4

Posted by Ryan Carson
Ryan Carson
23,287 Points

Why not add a '$' to the beginning of this variable?

Andrew said it's good convention to add something to the beginning of a variable if it's a jQuery object, like this:

var $overlay = $('<div id="overlay"></div>');

So why doesn't he add the '$' to the beginning of the imageLocation var?

var imageLocation = $(this).attr("href");

like this ... 

var $imageLocation = $(this).attr("href");

2 Answers

Chris Malcolm
Chris Malcolm
2,909 Points
Chris Malcolm
Chris Malcolm
2,909 Points

the attribute "href" of the jquery object would return a string, not a jquery object so technically his convention is correct.

Andrew Chalkley
Andrew Chalkley
Treehouse Guest Teacher
Andrew Chalkley
Andrew Chalkley
Treehouse Guest Teacher

Spot on Chris Malcolm!

Ryan Carson - with the $overlay you can call all the jQuery methods on it like hide() and show(). With the imageLocation it's just a plain JavaScript string and you can only call String methods on it, like toUpperCase(), not jQuery methods. Having the $ at the beginning just helps you remember which variables are jQuery objects.

Ryan Carson
Ryan Carson
23,287 Points

Gracias! :)

Andrew Chalkley - side note - why are questions associated to jQuery Basics automatically tagged with HTML instead of JavaScript? I had to change this one manually.

Andrew Chalkley
Andrew Chalkley
Treehouse Guest Teacher
Andrew Chalkley
Andrew Chalkley
Treehouse Guest Teacher

Good question...I'll bring it up with the community team.

James Gill
PLUS
James Gill
Courses Plus Student 34,936 Points
James Gill
James Gill
Courses Plus Student 34,936 Points

Other than as a convention for clarity, it shouldn't matter. From the jQuery documentation:

"Many developers prefix a $ to the name of variables that contain jQuery objects in order to help differentiate. There is nothing magic about this practice – it just helps some people keep track of what different variables contain." http://learn.jquery.com/using-jquery-core/jquery-object/