IE11 MutationObserver funny bug.

IE 11 MutationObserver's funny bug.md

IE 11 MutationObserver funny bug.

If you use mutation observer to detect element's style attribute changes, make sure that it's working good in IE11. :)
It turns out that mutation will not be generated in case when element's style is being changed using setProperty method.

element.style.setProperty( 'display', 'block' );

The funny thing is that it will work if you write.

element.style.display = 'block';

So here is the solution for this bug ( bugfix hack is funny as well :) ).

ie11mobugfix.js

( function () {
	if( !window.MutationObserver )
  		return;
	var example = document.createElement( '_' ),
	    observer = new MutationObserver( function () {} );
	observer.observe( example, { attributes: true } );

	//	Randomly changing style attribute using setProperty method.
	example.style.setProperty( 'display', 'block' );

	//	If no mutation record generated, than it's IE11 and it's a bug :)
	if( !observer.takeRecords().length ) {
		( function ( original ) {
			CSSStyleDeclaration.prototype.setProperty = function setProperty( name, to_value ) {
				var value = this.getPropertyValue( name ),
					priority = this.getPropertyPriority( name ),
					result = original.apply( this, arguments );

				//	HACK!
				//	If something modified after setProperty call, generate mutation by appending white space to cssText.
				if( value != this.getPropertyValue( name ) || priority != this.getPropertyPriority( name ) ) 
					this.cssText += ' ';
				return result;
			};
		} ) ( CSSStyleDeclaration.prototype.setProperty );
	}
} ) ();