javascript node has parent with class

1/**
2     * If the element/node ('child') has the class 'classname' => return true
3     * Else: call the function again with parent until parent with class is found or no parent is left
4*/
5function hasParentClass(child, classname){
6  if(child.className.split(' ').indexOf(classname) >= 0) return true;
7  try{
8    //Throws TypeError if child doesn't have parent any more
9    return child.parentNode && hasParentClass(child.parentNode, classname);
10  }catch(TypeError){
11    return false;
12  }
13}