March 26, 2002 - Using "*[@]" to Match DOMDocument Nodes by Attribute Names | WebReference

March 26, 2002 - Using "*[@]" to Match DOMDocument Nodes by Attribute Names

Yehuda Shiran March 26, 2002
Using "*[@]" to Match DOMDocument Nodes by Attribute Names
Tips: March 2002

Yehuda Shiran, Ph.D.
Doc JavaScript

You can use attribute names to match DOMDocument's nodes. For example, The pattern *[@dvds_rented] matches all nodes having the attribute dvds_rented in mydvd7.xml. The context may change. The pattern /*[@dvds_rented] will match nodes only at the root. The pattern //*[@dvds_rented] will match nodes any level below the root (try it):

  var matchedNodes = xmlDoc.selectNodes('//*[@dvds_rented]');
  alert("Number of matched nodes: " + matchedNodes.length);
The pattern @dvds_rented will match nodes at the current level. If the context is the first week of January, we should get a single week node (try it):

  var matchedNodes = xmlDoc.childNodes[3].childNodes[1].childNodes[0].
    childNodes[1].selectNodes('@dvds_rented');
  alert("Number of matched nodes: " + matchedNodes.length);
Similar patterns are also possible. The pattern week/@dvds_rented will match 4 nodes when the context is the month of January (try it):

  var matchedNodes = xmlDoc.childNodes[3].childNodes[1].childNodes[0].
    selectNodes('week/@dvds_rented');
  alert("Number of matched nodes: " + matchedNodes.length);
Here is mydvd7.xml for your reference:

<?xml version="1.0"?>
<?xml-stylesheet type="text/xsl" href="mydvd7.xsl"?>
<!DOCTYPE sales SYSTEM "mydvd7.dtd">
  <sales>
    <summary>
      <heading>MyDVD Rental Store</heading>
      <subhead>Periodical Sales Report</subhead>
      <description>Sales Report for January, February, 
	    and &lt;&month;&gt; of 2001</description>
      <author>author: &preparedby;</author>
      <date>Jan 30, 2002</date>
    </summary>
    <data>
      <month>
        <name>January 2001</name>
        <week number="1" dvds_rented="12000" />
        <week number="2" dvds_rented="15000" />
        <week number="3" dvds_rented="18000" />
        <week number="4" dvds_rented="11800" />		  
      </month>
      <month>
        <name>February 2001</name>
        <week number="1" dvds_rented="11500" />
        <week number="2" dvds_rented="12390" />
        <week number="3" dvds_rented="19050" />
        <week number="4" dvds_rented="11200" />		  
      </month>
      <month>
        <name>March 2001</name>
        <week number="1" dvds_rented="15300" />
        <week number="2" dvds_rented="12390" />
        <week number="3" dvds_rented="10050" />
        <week number="4" dvds_rented="11230" />		  
      </month>
    </data>
  </sales>