Question

I was asked to help add an onChange to a select so I came up with this:

$("select[name=component]").change(function() {
  $("input[name=Code]").val(JSONObject[$(this).selectedIndex].code;  
  $("input[name=Category]").val(JSONObject[$(this).selectedIndex].category;  
  $("input[name=UOM]").val(JSONObject[$(this).selectedIndex].uom;  
});

The asker told me it didn’t work until he changed $(this) to this

That only makes sense to me, if jQuery does not use the name selectedIndex of what I assume is a jQuery object.

If not, would I just need to use .attr("selectedIndex")?

Is jQuery converting the object on the fly from $(this) (jQuery object) to a form element or select object?

Answer 1

The jQuery object is not really an extension of the DOM element: The DOM element becomes a child of the jQuery one.

It is in the 0 member of the jQuery object, so if for some reason one needs to use the jQuery object (which as @nickf in the context of this example is insane – you would just use this.selectedIndex instead), one would have to use

$(this)[0].selectedIndex

to access the original attribute.