Why don't Safari and Firefox add a class to the label?

Question

JavaScript

Hello. There is a set of label and input, if input cheked a class is added to the label. Everything works in chrome and opera, but not in safari and mozilla.
This is how I check the input and add the class

$(".color_f .ch_input:checked").parent().addClass("active");

Why does it work in some browsers and not in others?