Create XML DOM Element while keeping case sensitivity
You need to use createElementNS()/setAttributeNS() and provide the namespace, not only the alias/prefix. The example uses urn:v as namespace.
var xmlns_v = "urn:v";var newCustprop = document.createElementNS(xmlns_v, "v:custProps");var newcp = document.createElementNS(xmlns_v, "v:cp");newcp.setAttributeNS(xmlns_v, "v:nameU", "Cost");newCustprop.appendChild(newcp);var xml = (new XMLSerializer).serializeToString(newCustprop);xml:
<v:custProps xmlns:v="urn:v"><v:cp v:nameU="Cost"/></v:custProps>
It's not recommended to use document.createElement for qualified names. See if the document.createElementNS can better serve your purposes.