Trying to use the SUM function on an attribute

I have the following xml:

<sub-root>
<Row attr1="10.00" attr2="Val1" />
<Row attr1="20.00" attr2="Val2" />
<Row attr1="30.00" attr2="Val3" />
</sub-root>

I would like to do the following in JScript:

var totalVal = xmlToSum.selectSingleNode("sum(///@attr1")

But when I try to open this page, I get an error "Expected Identifier".

What would be the proper syntax.

Peter
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Peter DeSimone

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