It would be better not to use $.each in this case. Use $.grep instead. This loops through an array in pretty much the same way as $.each with one exception. If you return true from the callback, the element is retained. Otherwise, it is removed from the array.

Your code should look something like this:

items = $.grep(items, function (el, i) {
    if (i === 5) { // or whatever
        return false;
    }

    // do your normal code on el

    return true; // keep the element in the array
});

One more note: this in the context of a $.grep callback is set to window, not to the array element.

I'm guessing you want $.map. You can return null to remove an item, and not worry about how indices might shift:

items = $.map(items, function (item, index) {
    if (index < 10) return null; // Removes the first 10 elements;
    return item;
});

If you want to remove an element from array, use splice()

var myArray =['a','b','c','d'];
var indexToRemove = 1;
// first argument below is the index to remove at, 
//second argument is num of elements to remove
myArray.splice(indexToRemove , 1);

myArray will now contain ['a','c','d']