Question

It seems odd that grep does not work with an optional selector argument – the existing way you call grep seems to fall outside JQuery conventions. In other words, this works:

$.grep($('div'), function(div) { return div.className == 'section' });

This does not:

$('div').grep(function(div) { return div.className == 'section' });

Furthermore, because of this it becomes tricky to search a list of tags – the first line of code, while it works, returns a flat array instead of a nice chainable JQuery object you can call .css() etc on.

Is there a good reason for grep to work this way in JQuery?

Answer 1

The function you are looking for is the second (callback) variant of $.fn.filter().

It works much the same way as $.grep, but acts on a jQuery object, and returns a jQuery object of all of the elements that returned true from the callback function, e.g.:

$('div')
.filter(function() {
    return this.className == 'section'
})
.css( ... ) ;