I am answering my own post with an update: I solved the issue. The string used to set the cookie had syntax that Safari, and Opera would not allow. That was due to a subtile and important issue with a for loop: a missing break statement. So the difference between Safari (and Opera) and Firefox, Chrome is the cookie string syntax. If secure is specified, it should be in the string by itself and not set to anything. The issue I tracked down was that 'secure=false;' was showing up in the string when it is just set by the presence of absence of 'secure' Thank you for time and attention JK