Hi. Thank You for the article. There seems to be an error in the example of "Object.hasOwnProperties()" though: there should be "obj.hasOwnProperty("name")" instead of "Object.hasOwnProperty("name") - if the name of the variable will not be changed (I'd suggest "object" by the way) - I believe. I also wonder if a complexity of operations such as calling "values" may not be different depending on the specific engine implementation. Also would be cool to see some sources You've based on. Bless!J3:16