WebAssembly in Action

Author of the book "WebAssembly in Action"
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The book's original source code can be downloaded from the Manning website and GitHub. The GitHub repository includes an updated-code branch that has been adjusted to work with the latest version of Emscripten (currently version 3.1.44).

Monday, March 28, 2011

DOMParser's parseFromString function and IE 9

When Internet Explorer 9 is running in Standards mode the DOMParser object is now available.

The DOMParser object allows one to convert a string of XML into a document object by calling the DOMParser's parseFromString function.

This article will focus only on the DOMParser object and will not do the standard feature detection tests that should be done for cross-browser compatibility (this code will break if IE 9 is not running in Standards mode or if you are using a previous version of IE).

If you are interested in seeing how to do proper feature detection tests for the DOMParser object, the following article has an example function called ConvertStringToXMLObject:

Something to be aware of with the DOMParser's parseFromString function is that the resulting XML document may have attributes that are rearranged compared to the attributes of the XML string that was passed in.

For example, if we have the following string of XML one would expect that the resulting XML document object would be an exact replica of the original XML string:
var sXML = "<TEST ID=\"124\" TITLE=\"TitleValue\" DATE=\"2011-02-24T00:00:00\" STATUS=\"Processing\" EMPNAME=\"Smith, Sam\" STATUSCODE=\"P\" ROWNUM=\"1\" />";

What has been discovered, however, is that if you pass the above XML string into the DOMParser's parseFromString function, the attributes in this case are completely reversed:
var dpParser = new DOMParser();
var xdDoc = dpParser.parseFromString(sXML, "text/xml");

// Grab the root 'Test' node from the document object and then
// loop through the attributes

var xnTest = xdDoc.getElementsByTagName("TEST")[0];
var xaAttrib = null;
var iAttribCount = xnTest.attributes.length;
for (var iIndex = 0; iIndex < iAttribCount; iIndex++){
// Grab the current attribute and display its name
xaAttrib = xnTest.attributes[iIndex];

The result shows that the XML attributes passed in are now in reverse order:
<TEST ROWNUM="1" STATUSCODE="P" EMPNAME="Smith, Sam" STATUS="Processing" DATE="2011-02-24T00:00:00" TITLE="TitleValue" ID="124" />

A bug was filed with Microsoft on this issue but, unfortunately, Microsoft has indicated that the parseFromString behavior is by design.

The best advice that can be given for this situation is to not iterate over the attributes using indexes and instead to grab the attribute values by name as in the following example:
var xnTest = xdDoc.getElementsByTagName("TEST")[0];
var sID = xnTest.getAttribute("ID");


  1. Nice postings Gerard,

    I work for a developer content sharing site, and I thought you might be interested in a few opportunities for some web builder content. Send me an email at mitch [at] dzone {dot} com and I'll explain more.

  2. All my xml files in IE9 will display attributes of XML in reversed or inverted order. It is really harassing. Moreover, IE takes a long time to open XML files. Chrome and firefox has no such problem. IE8 won't have such problems

  3. I used this but now I need to grab the xml from the object returned by the DOMParser. How to do that?? I would like to use xpath.