the $ in backbone.js View

Question

What's the difference between jQuery $ and this.$ in Backbone.js View? in a View, I listened to a collection's reset event to empty an element by using below code

//code in View
this.$("#the_id").empty();

however it did not empty my element, then I changed the code to

$("#the_id").empty();

this time it works. so, why this.$ does not do the work?

Answer 1

Calling this.$( selector ) in a view is same as calling $( selector, this ) or $(this).find( selector ).

It gives context for the selector I.E. only elements under this are searched to match the selector whereas normal jQuery $(selector) starts the search from the entire document's root.

Your view should not manipulate elements that it doesn't own, if calling this.$("#the_id").empty(); doesn't do anything it means that the element wasn't under the view's "area of control" or doesn't exist to begin with.