How to modify XML request payload using Javascript?

[pxzxz1]

Hello Apigeeks,

1. How do I update value in XML that comes from request payload?

2. How do I insert new element to the XML that comes from request payload?

For both items mentioned above, I tried with Javascript object model

var name = context.targetRequest.body.asXML.name;
request.content.asXML
context.proxyRequest.content.asXML

Unfortunately, these does not help me to do what I want. Basically,

1. I want to modify a value in XML, say <amount>0</amount> update to <amount>200</amount>

2. I want to add new element to the XML, say <student><name>Thomson</name></student> to <student><id>xx123</id><name>Thomson</name></student>

Not sure if it's matter, but it is a SOAP XML.