Adding custom namespace to xml element in javascript

Similar question, that did not provide actual answer for me How to add additional xmlns namespace attributes to XML in javascript .

I'm trying to add custom namespace to xml element, i was using pure jquery and it worked fine in chrome. I was using this jquery statement to get element string in jquery

$(schemaXml).find('Field').prop('outerHTML')

Unfortunately it does not work with IE.

I tried adding namespace before parsing and IE just toss it out (at least from element itself).

Here is the code sample

schemaXml = DOMParser().parseFromString(oldSchemaXmlStr, "text/xml")
console.log("Got XML from field:");
console.log(oldSchemaXmlStr);
console.log("Parsed it as:");
console.log((XMLSerializer()).serializeToString(schemaXml.getElementsByTagName('Field')[0]));
$(schemaXml).find('Field').attr('sntMB:Functionality', "Atachments");    
console.log("Added sntMB:Functionality to XML:");
console.log((XMLSerializer()).serializeToString(schemaXml.getElementsByTagName('Field')[0]));

And this is the output in IE console

Got XML from field:
<Field ID="{fa564e0f-0c70-4ab9-b863-0177e6ddd247}" Type="Text" Name="Title" ShowInNewForm="FALSE" ShowInFileDlg="FALSE" DisplayName="Title" Sealed="TRUE" SourceID="http://ift.tt/1k7JiLs" StaticName="Title" ColName="nvarchar7" Description="" xmlns:sntMB="SnT.MagicBox" />
Parsed it as:
<Field ColName="nvarchar7" StaticName="Title" SourceID="http://ift.tt/1k7JiLs" Sealed="TRUE" DisplayName="Title" ShowInFileDlg="FALSE" ShowInNewForm="FALSE" Name="Title" Type="Text" ID="{fa564e0f-0c70-4ab9-b863-0177e6ddd247}" Description="" />
Added sntMB:Functionality to XML:
<Field ColName="nvarchar7" StaticName="Title" SourceID="http://ift.tt/1k7JiLs" Sealed="TRUE" DisplayName="Title" ShowInFileDlg="FALSE" ShowInNewForm="FALSE" Name="Title" Type="Text" ID="{fa564e0f-0c70-4ab9-b863-0177e6ddd247}" xmlns:NS1="" NS1:sntMB:Functionality="Attachments" Description="" />