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Scoped absolute paths in querySelector/All

From: Brett Zamir <brettz9@gmail.com>
Date: Sat, 07 Sep 2013 09:13:11 +0800
Message-ID: <522A7DA7.2000703@gmail.com>
To: public-webapps@w3.org
I am wondering whether thought has been given to allowing selectors 
beginning with ">" for use with querySelector/All such as:

     " > .sharedClass"

Sometimes one wishes to resolve a precise hierarchy but relative to the 
current element. Currently, to do so with precision, one must either 
specify a path starting from the document root, a unique ID, or use 
other scripting methods.

Having such an option would provide the same convenience for precise 
access as XPath or to a lesser extent, as JSON, allow.

The following document illustrates the concern--in this case, where we 
are trying to get only the second span relative to "#div1" but without 
needing to specify or be aware of the whole document hierarchy:

<!DOCTYPE html><html><head><meta charset="utf-8" /></head><body>

<div id="div1">
     <span class="sharedClass">First</span>
     <div>
         <span class="sharedClass">Second</span>
     </div>
</div>

<script>

   var s = document.querySelector('#div1');

   // The following gets both spans instead of the one directly inside 
that we want
   var relativeSelector = s.querySelectorAll('.sharedClass');
   alert(relativeSelector.length); // 2

   // The following gets the desired span, but required us to specify 
the full path or redundantly express the path to our parent again
   var absoluteSelector = s.querySelectorAll('#div1 > .sharedClass');
   alert(absoluteSelector[0].textContent); // "First"

</script></body></html>

(Although the use case would be far less common, a path might also begin 
with ">" when run against documents to allow usage with XML documents 
where a path was desired relative to the root but without committing to 
a specific root element.)

It would also be nice to be able to modify the element or 
elements--e.g., if there were a removeSelector(sel) analogue to the 
ability to use "delete obj.prop.prop2" on a JSON object, a 
replaceSelector(sel, el) convenience method, etc..

Best,
Brett
Received on Saturday, 7 September 2013 01:13:57 UTC

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