chrisrbailey's comment on this question:


helped me solve that exact same issue I was having with a slider. I'd like to extend that example into another question. Could someone help me understand the difference between these two examples:

  slide:  function(event,ui){$('#field1').val(ui.value)}

  slide:  function(event,ui){$('#field1').val($(this).slider("value"))}

As the aforementioned question/answer indicates, ui.value and $(this).slider("value") are actually grabbing different things. I'm not used to the ui.value and was wondering if anyone had a good explanation/link to tutorial that talks more about using the 'event,ui' items in jQuery.


The jquery-ui documentation tells you which parameters are passed to which callback functions. Unfortunately, the documentation isn't always that great at describing what kind of data those parameters have. If you take a look at http://jqueryui.com/demos/slider/, Events tab, expand to display information about the Slide event.

This event is triggered on every mouse move during slide. Use ui.value (single-handled sliders) to obtain the value of the current handle, $(..).slider('value', index) to get another handles' value.

Return false in order to prevent a slide, based on ui.value.

Ken Browning
+2  A: 

Have you checked out the documentation?

I've put together a demo that writes out the property of each object to the screen, so you can see what each contains. It's interesting to note that ui.value and $(this).slider("value") return different values (0 and 1, respectively) when one starts to slide the slider (one slider increment leads to values 1 and 0, respectively). From that point on, they also seem to be off by one (this is on Firefox 3.5.3 for me).

Russ Cam
+1 Cool demo....
Robert Harvey
I have checked the documentation, and it's a bit vague. Is ui object (it is an object, right?) a part of every UI component, or is this something unique to just the slider component?
yes, UI is an object. From the demo, we can see it has two properties, **handle** and **value**. It is not unique to the slider UI component (take a look at tabs, accordion and progressbar events for instance), but it is not a defacto standard within plugins as far as I've seen. It looks as though the jQuery UI library has tried to standardize the event handler signatures within the widgets it offers.
Russ Cam