JavaScript: How to get text from all descendents of an element, disregarding scripts?

Question

My current project involves gathering text content from an element and all of its descendents, based on a provided selector.

For example, when supplied the selector #content and run against this HTML:

<div id="content">
  <p>This is some text.</p>
  <script type="text/javascript">
    var test = true;
  </script>
  <p>This is some more text.</p>
</div>

my script would return (after a little whitespace cleanup):

This is some text. var test = true; This is some more text.

However, I need to disregard text nodes that occur within <script> elements.

This is an excerpt of my current code (technically, it matches based on one or more provided selectors):

// get text content of all matching elements
for (x = 0; x < selectors.length; x++) { // 'selectors' is an array of CSS selectors from which to gather text content
  matches = Sizzle(selectors[x], document);
  for (y = 0; y < matches.length; y++) {
    match = matches[y];
    if (match.innerText) { // IE
      content += match.innerText + ' ';
    } else if (match.textContent) { // other browsers
      content += match.textContent + ' ';
    }
  }
}

It's a bit overly simplistic in that it just returns all text nodes within the element (and its descendants) that matches the provided selector. The solution I'm looking for would return all text nodes except for those that fall within <script> elements. It doesn't need to be especially high-performance, but I do need it to ultimately be cross-browser compatible.

I'm assuming that I'll need to somehow loop through all children of the element that matches the selector and accumulate all text nodes other than ones within <script> elements; it doesn't look like there's any way to identify JavaScript once it's already rolled into the string accumulated from all of the text nodes.

I can't use jQuery (for performance/bandwidth reasons), although you may have noticed that I do use its Sizzle selector engine, so jQuery's selector logic is available.

Thanks in advance for any help!

Answer 1

function getTextContentExceptScript(element) {
    var text= [];
    for (var i= 0, n= element.childNodes.length; i<n; i++) {
        var child= element.childNodes[i];
        if (child.nodeType===1 && child.tagName.toLowerCase()!=='script')
            text.push(getTextContentExceptScript(child));
        else if (child.nodeType===3)
            text.push(child.data);
    }
    return text.join('');
}

Or, if you are allowed to change the DOM to remove the <script> elements (which wouldn't usually have noticeable side effects), quicker:

var scripts= element.getElementsByTagName('script');
while (scripts.length!==0)
    scripts[0].parentNode.removeChild(scripts[0]);
return 'textContent' in element? element.textContent : element.innerText;

Answer 2

EDIT:

Well first let me say im not too familar with Sizzle on its lonesome, jsut within libraries that use it... That said..

if i had to do this i would do something like:

var selectors = new Array('#main-content', '#side-bar');
function findText(selectors) {
    var rText = '';
    sNodes = typeof selectors = 'array' ? $(selectors.join(',')) : $(selectors);
    for(var i = 0; i <  sNodes.length; i++) {
       var nodes = $(':not(script)', sNodes[i]);
       for(var j=0; j < nodes.length; j++) {
         if(nodes[j].nodeType != 1 && node[j].childNodes.length) {
             /* recursion - this would work in jQ not sure if 
              * Sizzle takes a node as a selector you may need 
              * to tweak.
              */
             rText += findText(node[j]); 
         }  
       }
    }

    return rText;
}

I didnt test any of that but it should give you an idea. Hopefully someone else will pipe up with more direction :-)

---

Cant you just grab the parent node and check the nodeName in your loop... like:

if(match.parentNode.nodeName.toLowerCase() != 'script' && match.nodeName.toLowerCase() != 'script' ) {
    match = matches[y];
    if (match.innerText) { // IE
      content += match.innerText + ' ';
    } else if (match.textContent) { // other browsers
      content += match.textContent + ' ';
    }
}

ofcourse jquery supports the not() syntax in selectors so could you just do $(':not(script)')?