How to process xml string in javascript

Dear All I have soap response with following structure

<?xml version="1.0" encoding="UTF-8"?>
<SOAP-ENV:Envelope xmlns:SOAP-ENV="http://ift.tt/sVJIaE" xmlns:SOAP-ENC="http://ift.tt/wEYywg" xmlns:ns1="http://ift.tt/1oZRuRo" xmlns:ns2="http://ift.tt/1oZRxg3" xmlns:ns3="http://ift.tt/1oZRuRq" xmlns:ns4="http://ift.tt/1oZRxg5" xmlns:ns5="http://ift.tt/1oZRuRw" xmlns:ns6="http://ift.tt/1oZRuRA" xmlns:ns8="http://ift.tt/1xDuHdm" xmlns:xsd="http://ift.tt/tphNwY" xmlns:xsi="http://ift.tt/ra1lAU">
   <SOAP-ENV:Header />
   <SOAP-ENV:Body>
      <ns1:SLIAnswer>
         <ns1:Ver />
         <ns1:ResponseData>
            <ns1:ResultAndAddInfo>
               <ns1:Result>
                  <ns1:Result>SYSTEM_FAILURE</ns1:Result>
                  <ns1:ResultId>1</ns1:ResultId>
               </ns1:Result>
            </ns1:ResultAndAddInfo>
         </ns1:ResponseData>
      </ns1:SLIAnswer>
   </SOAP-ENV:Body>
</SOAP-ENV:Envelope>

From this string I want to fetch all the child node in "ResponseData" node , and its values how I can do this using javascript