mootools-core.js error

In the process of finding solution to another error I am using developer tools on firefox.  My css is showing several errors - most I think are due to not being standardized yet but I am still kind of new to all this.

I came across this error in my mootools-core.js file:

Use of getAttributeNode() is deprecated. Use getAttribute() instead.

Here is the line of code said to contain the error:

d.value:d.get("text"))==a)return d.selected=true}},get:function(){var a=this,b=a.get("tag");if(b!="select"&&b!="option")return this.getProperty("value");if(b=="select"&&!(a=a.getSelected()[0]))return"";return(b=a.getAttributeNode("value"))&&b.specified?a.value:a.get("text")}};b=null;if(document.createElement("div").getAttributeNode("id"))Element.Properties.id={set:function(a){this.id=this.getAttributeNode("id").value=a},get:function(){return this.id||null},erase:function(){this.id=this.getAttributeNode("id").value=

I need to know what is wrong with this line of code so I may correct it - maybe it will solve my original issue - but even if it doesn't I still want my code as correct as possible.

Or is this just another non-standardized thing?

Don't understand the point thing yet since I am still new to this site.  

Your help is most appreciated.