You will have questions about the properties of objects, for example if objects are passed by value or by reference. The answer to this question is that all objects go by reference. Any modification of an object reference changes the object itself. Finally, be prepared to face specific examples. You may be asked if the object returned by document.getElementsByTagName () is an array. (No. This is an HTML compilation.) You won’t know what the examples will be, so take some time each evening before the interviews to study a series of sample questions to prepare for the interview.