xpath expression for numeric comparison

I'm writing a Greasemonkey script so can't change the source XHTML.

Given the following XHTML fragment:

<td>
    <span class="entry">Gender, Age:</span> Female, 42<br>
    <span class="entry">Country, Town:</span> United Kingdom, London 
    <span class="small09"></span>
</td>

is it possible to write an expression that can be evaluated using document.evaluate that will allow me to select all entries where the age is greater than, say, 40? I want something such as the following:

var matches = document.evaluate("//table[tbody/tr[2]/td[1][number(SOMEHOW 
  MA开发者_运维问答TCH THE AGE PART) > 40]]", 
  document, null, XPathResult.UNORDERED_NODE_SNAPSHOT_TYPE, 
  null);

Thanks

---

Use:

//table[tbody/tr[2]/td[1]
  [number(
    substring-after(normalize-space(span[1]/following-sibling::text()[1]),
                   ',')
          ) 
   > 
     40
    ] 
       ]

---

You can't use conditionals on text content, but you can filter the results with JavaScript.

Something like this should work:

var targetCells     = document.evaluate (
                        "//table/tbody/tr[2]/td[1]",
                        document,
                        null,
                        XPathResult.UNORDERED_NODE_SNAPSHOT_TYPE,
                        null
                    );

for (var J = targetCells.snapshotLength - 1;  J >= 0;  --J)
{
    var thisCell    = targetCells.snapshotItem (J);

    //--- Get the age.  Key off (fe)male, {age in decimal years}<br> in the text of the table cell
    var ageTxt      = thisCell.textContent.match (/male[, ]+(\d+)/i);

    if (ageTxt  &&  ageTxt.length > 1)
    {
        var age     = parseInt (ageTxt[1]);
        if (age > 40)
        {
            //-----------------------
            //--- DO YOUR STUFF HERE.
            //-----------------------
        }
    }
}

---

If you set age as an attribute you can access that value.

Something like

<Person Gender="F" Age="42" />