Question

Is there any benefit (performance or otherwise) for me to use the .eq(0) filter when I reference the body tag in a jQuery object? For instance: $(“body”).eq(0) as opposed to just $(“body”).

Answer 1

No $("body") should do just fine.. eq(0) is just to pick the first element and it won’t make any difference if it has just one element to begin with.

$('body') will have the same structure as $('body').eq(0) but .eq is just an extra call.

.eq function implementation

function (i) {
    i = +i;
    return i === -1 ? this.slice(i) : this.slice(i, i + 1);
}

As you see, it doesn’t make sense to do a eq when you just have only one element.