How to check the XML empty value?

How to check the XML empty value?

Hi,
 
Can anyone teach me how to check the XML result is empty?
 
I have
 
  1. productRec.open = (r.executeXPath("/record/price/text()")).toDecimal());
 
Normal the xml will show
<price>12.01 </price>
However, when there is no value sometimes, the xml show
<price/>
 
I have try
 
  1.             priceChk = r.executeXPath("/quote/price/text()");
  2.             if ((priceChk ="")||(priceChk.length()=0)||(priceChk=null))
  3.             {
  4.                 productRec.open = 0.0;
  5.             }
But still can't solve the problem.
Thank you so much.
 
Kevin.