Node.normalize() crashes in IE6

Question

I am doing some manipulation of TextNodes in javascript, and I (unfortunately) need to support IE6. Node.normalize() is crashing, and I need to work around this. My first inclination is to just re-implement it using other DOM methods. How would I implement this?

Answer 1

You'd need to recursively look through all of the child nodes of the current node. When considering a node, you'd delete any empty text nodes and combine any adjacent text nodes.

 function myNormalize( node )
     for each child node of node do
         if child is not text
            normalize(child)
         else
            if child node is empty
               delete
               continue
            else 
                sibling = next node
                while sibling exists and sibling is a text node
                    if sibling is empty
                       delete sibling
                    else
                       combine sibling with child
                    get next sibling
                end
            end
        end
    end
end

Answer 2

based on tvanfosson's pseudocode, here's what I came up with in javascript:

var ELEMENT_NODE = 1;
var TEXT_NODE = 3;
function normalize(node) {
    for (i=0; i<node.childNodes.length; i++) {
        var child = node.childNodes[i];
        if (child.nodeType == ELEMENT_NODE) {
            normalize(child);
            continue;
        }
        if (child.nodeType != TEXT_NODE) { continue; }
        var next = child.nextSibling;
        if (next == null || next.nodeType != TEXT_NODE) { continue; }
        var combined_text = child.nodeValue + next.nodeValue;
        new_node = node.ownerDocument.createTextNode(combined_text);
        node.insertBefore(new_node, child);
        node.removeChild(child);
        node.removeChild(next);
        i -= 1;
    }
}

Answer 3

The solution above was running very slow and crashing Firefox for me. So I optimized it a bit and it's working great now (the main issue was with repeatedly referencing the HTML collection object node.childNodes).

Thanks for the great starting point, but I figured this was worth posting:

function myNormalize(node) {
    for (var i=0, children = node.childNodes, nodeCount = children.length; i<nodeCount; i++) {
        var child = children[i];
        if (child.nodeType == 1) {
            myNormalize(child);
            continue;
        }
        if (child.nodeType != 3) { continue; }
        var next = child.nextSibling;
        if (next == null || next.nodeType != 3) { continue; }
        var combined_text = child.nodeValue + next.nodeValue;
        new_node = node.ownerDocument.createTextNode(combined_text);
        node.insertBefore(new_node, child);
        node.removeChild(child);
        node.removeChild(next);
        i--;
        nodeCount--;
    }
}