| <!DOCTYPE html> |
| <script src="../../../resources/testharness.js"></script> |
| <script src="../../../resources/testharnessreport.js"></script> |
| <style> |
| .overflow { |
| counter-reset: c 0; |
| } |
| |
| .overflow h3:before { |
| counter-increment: c 500000000; |
| } |
| |
| .underflow { |
| counter-reset: c 0; |
| } |
| |
| .underflow h3:before { |
| counter-increment: c -500000000; |
| } |
| |
| h3::before { |
| content: counter(c); |
| } |
| </style> |
| <div id="headings"> |
| </div> |
| <script> |
| var headings = document.getElementById('headings'); |
| var items = []; |
| |
| for (var i = 0; i < 5; i++) { |
| items.push(document.createElement('h3')); |
| headings.appendChild(items[i]); |
| } |
| |
| function get_list_counters() { |
| var counters = []; |
| for (var i = 0; i < items.length; i++) { |
| counters.push(parseInt(internals.counterValue(items[i]))); |
| } |
| return counters; |
| } |
| |
| /* The spec [1] allows implementation-specific limits on the value of counters. |
| The only requirement is that "If an increment would push the counter’s value |
| beyond these limits, the increment must be ignored, and the counter’s value |
| remain unchanged." |
| |
| We assume a 32 bit int limit. |
| */ |
| test(function() { |
| headings.className = 'overflow'; |
| assert_array_equals(get_list_counters(), |
| [500000000, 1000000000, 1500000000, 2000000000, 2000000000]); |
| }, 'large reset does not overflow'); |
| |
| test(function() { |
| headings.className = 'underflow'; |
| assert_array_equals(get_list_counters(), |
| [-500000000, -1000000000, -1500000000, -2000000000, -2000000000]); |
| }, 'small reset does not underflow'); |
| |
| </script> |
