function _xlsxToStrings( obj ) {
	if ( _ieExcel === undefined ) {
		// Detect if we are dealing with IE's _awful_ serialiser by seeing if it
		// drop attributes
		_ieExcel = _serialiser
			.serializeToString(
				$.parseXML( excelStrings['xl/worksheets/sheet1.xml'] )
			)
			.indexOf( 'xmlns:r' ) === -1;
	}

	$.each( obj, function ( name, val ) {
		if ( $.isPlainObject( val ) ) {
			_xlsxToStrings( val );
		}
		else {
			if ( _ieExcel ) {
				// IE's XML serialiser will drop some name space attributes from
				// from the root node, so we need to save them. Do this by
				// replacing the namespace nodes with a regular attribute that
				// we convert back when serialised. Edge does not have this
				// issue
				var worksheet = val.childNodes[0];
				var i, ien;
				var attrs = [];

				for ( i=worksheet.attributes.length-1 ; i>=0 ; i-- ) {
					var attrName = worksheet.attributes[i].nodeName;
					var attrValue = worksheet.attributes[i].nodeValue;

					if ( attrName.indexOf( ':' ) !== -1 ) {
						attrs.push( { name: attrName, value: attrValue } );

						worksheet.removeAttribute( attrName );
					}
				}

				for ( i=0, ien=attrs.length ; i<ien ; i++ ) {
					var attr = val.createAttribute( attrs[i].name.replace( ':', '_dt_b_namespace_token_' ) );
					attr.value = attrs[i].value;
					worksheet.setAttributeNode( attr );
				}
			}

			var str = _serialiser.serializeToString(val);

			// Fix IE's XML
			if ( _ieExcel ) {
				// IE doesn't include the XML declaration
				if ( str.indexOf( '<?xml' ) === -1 ) {
					str = '<?xml version="1.0" encoding="UTF-8" standalone="yes"?>'+str;
				}

				// Return namespace attributes to being as such
				str = str.replace( /_dt_b_namespace_token_/g, ':' );
			}

			// Safari, IE and Edge will put empty name space attributes onto
			// various elements making them useless. This strips them out
			str = str.replace( /<([^<>]*?) xmlns=""([^<>]*?)>/g, '<$1 $2>' );

			obj[ name ] = str;
		}
	} );
}
Convert XML documents in an object to strings
@param  {object} obj XLSX document object