you can chaneg your onblur to be just onblur="yourFunc(this)"
In the future if you want to reference an object, you need to use document.getElementById or document.formName.elementName. IE IS BAD in the fact that if it can not find a variable named XXXX, it looks for form element ids/names that are XXXX. No other browser does that.
Another IE quirk is the name and id have to be the same if you use document.getElementById