Question

It may be a silly question but I haven’t been able to find any documentations on this on the internet.

When declaring variables to use within Javascript i normally use var x = 0 but I’ve seen in jQuery tutorials that they use $x = 0. What is the difference of those two ?

Also, would i call those two variables the same way or do i need to use the $ mark before ?
So for example : for(i=0; i < x; i++) or for(i=0; i < $x; i++)

Answer 1

Your var x = 0; is fine. The only reason people sometimes use a $ with jQuery-specific variables is that it helps them remember that the variable contains the result of a call to the $() function in jQuery. The $ is actually part of the variable name, so you would use $ everywhere you referred to the variable.

So this:

var x = $(".foo");      // Find all elements with class "foo"
x.css("color", "blue"); // Make them all blue

Is exactly the same as this:

var $x = $(".foo");      // Find all elements with class "foo"
$x.css("color", "blue"); // Make them all blue

They’ve just put a $ at the beginning of the name.

Note: You’ve quoted your “jQuery” example as simply $x = 0; (without var). Be sure you always declare your variables (using var); otherwise, you’re falling prey to the Horror of Implicit Globals.