Selector by ID with attribute behaves weirdly (and differently across browsers)

[alexvy86]

I was trying to determine if at least 1 checkbox in the page (all with the same name and id) is selected, using this code:

if ($("#dnisToReserve:checked").length == 0) {

alert("No numbers were selected."); return false;

}

I then found out that this SHOULD be wrong since a selector with # will only return 1 element (from the Documentation: "(#) Matches a single element with the given id attribute").

The documentation is right if I don't use the ":checked" attribute, but if I use it I get weird behavior.

• In IE, it seems that the first checkbox gets retrieved (by id, I guess), and then the ":checked" filter applied to it, so if it is checked then the condition in my code is false, but if I check any other checkbox and not the first, the condition is true (length only returns 1 or 0, depending on the state of the first checkbox).

• In Firefox, it seems to ignore the # selector completely, since the length property returns exactly the amount of checked checkboxes in the page (with that id/name, I didn't try combining checkboxes with a different id/name), no matter if the first one is checked or not.

[alexvy86]

Oh, if it serves any purpose, I did manage to do what I needed by using the following selector:

$(":checkbox[name=dnisToReserve]:checked").length

[dmethvin]

The ID attribute must be unique in a document.