TEXT_NODE: returns ONLY text?

I'm using JavaScript in order to extract all text from a DOM object. My algorithm goes over the DOM object itself and it's descendants, if the node is a TEXT_NODE type than accumulates it's nodeValue.

For some weird reason I also get things like:

#hdr-editions a { text-decoration:none; }
#cnn_hdr-editionS { text-align:left;clear:both; }
#cnn_hdr-editionS a { text-decoration:none;font-size:10px;top:7px;line-height开发者_JAVA百科:12px;font-weight:bold; }
#hdr-prompt-text b { display:inline-block;margin:0 0 0 20px; }
#hdr-editions li { padding:0 10px; }

How do I filter this? Do I need to use something else? I want ONLY text.

From the looks of things, you're also collecting the text from <style> elements. You might want to run a check for those:

var ignore = { "STYLE":0, "SCRIPT":0, "NOSCRIPT":0, "IFRAME":0, "OBJECT":0 }

if (element.tagName in ignore)
    continue;

You can add any other elements to the object map to ignore them.

You want to skip over style elements.

In your loop, you could do this...

if (element.tagName == 'STYLE') {
   continue;
}

You also probably want to skip over script, textarea, etc.

This is text as far as the DOM is concerned. You'll have to filter out (skip) <script> and <style> tags.

[Answer added after reading OP's comments to Andy's excellent answer]

The problem is that you see the text nodes inside elements whose content is normally not rendered by browsers - such as STYLE and SCRIPT tags.

When scan the DOM tree, using depth-first search I assume, your scan should skip over the content of such tags.

For example - a recursive depth-first DOM tree walker might look like this:

function walker(domObject, extractorCallback) {
    if (domObject == null) return; // fail fast
    extractorCallback(domObject);
    if (domObject.nodeType != Node.ELEMENT_NODE) return;
    var childs = domObject.childNodes;
    for (var i = 0; i < childs.length; i++)
        walker(childs[i]);
}

var textvalue = "":
walker(document, function(node) { 
    if (node.nodeType == Node.TEXT_NODE)
        textvalue += node.nodeValue;
});

In such a case, if your walker encounters tags that you know you won't like to see their content, you should just skip going into that part of the tree. So walker() will have to be adapted as thus:

var ignore = { "STYLE":0, "SCRIPT":0, "NOSCRIPT":0, "IFRAME":0, "OBJECT":0 }

function walker(domObject, extractorCallback) {
    if (domObject == null) return; // fail fast
    extractorCallback(domObject);
    if (domObject.nodeType != Node.ELEMENT_NODE) return;

    if (domObject.tagName in ignore) return; // <--- HERE

    var childs = domObject.childNodes;
    for (var i = 0; i < childs.length; i++)
        walker(childs[i]);
}

That way, if we see a tag that you don't like, we simply skip it and all its children, and your extractor will never be exposed to the text nodes inside such tags.