Question

I try put one element next second, and delete second element, but it does not work.
Look at example: http://jsfiddle.net/CZCGG/

Answer 1

The result of getElementsByTagName is a live node list. As you manipulate the elements the pseudo-array you have will get updated in real-time.

Specifically each time around the loop your i value is jumping too far ahead, because the element after the one you just removed now has that original element’s index.

To resolve that you should work from the end of the array backwards. This ensures that each element retains its original index as the loop progresses.

You should also use Node.replaceChild instead of an insertBefore, removeChild sequence

see http://jsfiddle.net/alnitak/pfnGX/

var  span = document.getElementsByTagName("span");

for (var i = span.length - 1; i >= 0; --i) {
    var a = document.createElement("a");
    a.href = "http://jsfiddle.net/";
    a.innerHTML = "http://jsfiddle.net/ " + i; 

    var s = span[i];
    s.parentNode.replaceChild(a, s);
}​