How to assign values from java script to a property in system class

(fullPath);
(objfile.files[0].name);
(objfile.files[0].size);
(objfile.files[0].type);

Public Property _SelFileAttributes As ArrayList
Get
    Return SelFileAttributes
End Get
 Set(value As ArrayList)
    SelFileAttributes = value
 End Set
End Property

var proHandler = {
      proHandler : "ProductionHandler",
      showUrlLink: function() {
      if ( this.proHandler === "ProductionHandler") {
      prodHandler._SelFileAttributes.Add(fullPath);
      prodHandler._SelFileAttributes.Add(objfile.files[0].name);
      prodHandler._SelFileAttributes.Add(objfile.files[0].size);
      prodHandler._SelFileAttributes.Add(objfile.files[0].type);
                                }
                   }
    }