javascript: How to check if an element is clickable or not

My naive approach is the following:

function isClickable(id){     
     elem = document.getElementById(id);
     if (elem.nodeName.toLowerCase() == 'a' || typeof(elem.click) != 'undefined'){
        return true;     
     }else{
        return false;     
     }
}    

Is there anything better I can do?