rem: if(element.document != undefined && element.document==null) return; Element.setStyle(element, {"background-color" : originalColor}); 
add: if (element.document != undefined && element.document == null) { return; } Element.setStyle(element, {"background-color" : element.originalColor}); 
context:     highlight : function(element) {    	        var highLightColor = "yellow";	        var originalColor = Element.getStyle(element, "background-color");        Element.setStyle(element, {"background-color" : highLightColor});        window.setTimeout(function() {	        if(element.document != undefined && element.document==null) return;            Element.setStyle(element, {"background-color" : originalColor});        }, 200);    }
meta: 3175	/local1/tlutelli/issta_data/temp/all_js/javascript/2006_temp/2006/3175/ec6623fd9e0ddb1c56b1a65fd8a5d205da7629e2/htmlutils.js/buggy/code/javascript/core/scripts/htmlutils.js