Can't check all the checkbox in JavaScript

I work on a web application and when running, my code don't even work. But if do

$("input[name^='show-points-']").attr("checked", false);

on the console, the checkboxes uncheck well.

Weird because, always in the console:

$("input[name^='show-points-']").attr("checked", "checked");

don't works.

In this Jsfiddle, the code works for the "uncheck" feature, but not the "check-all" one.