third_party/WebKit/LayoutTests/fast/events/scroll-event-handler-count.html

   1 <div id="scrolltarget">
   2 <script src="../../resources/js-test.js"></script>
   3 <script>
   4 description('This test checks that we correctly update the scroll event handler count as event handlers are added and removed');
   5 (function() {
   6     // Test addEventListener/removeEventListener on the document.
   7     var listener = function() { }
   8
   9     shouldBe('window.internals.scrollEventHandlerCount(document)', '0');
  10     document.addEventListener('scroll', listener, true);
  11     shouldBe('window.internals.scrollEventHandlerCount(document)', '1');
  12     document.addEventListener('scroll', listener, false);
  13     shouldBe('window.internals.scrollEventHandlerCount(document)', '2');
  14     document.removeEventListener('scroll', listener, true);
  15     shouldBe('window.internals.scrollEventHandlerCount(document)', '1');
  16
  17     // Try removing the capturing listener again.
  18     document.removeEventListener('scroll', listener, true);
  19     shouldBe('window.internals.scrollEventHandlerCount(document)', '1');
  20
  21     document.removeEventListener('scroll', listener, false);
  22     shouldBe('window.internals.scrollEventHandlerCount(document)', '0');
  23 })();
  24
  25 debug('Test setting onscroll on the document.');
  26 (function() {
  27     shouldBe('window.internals.scrollEventHandlerCount(document)', '0');
  28     document.onscroll = function() { }
  29     shouldBe('window.internals.scrollEventHandlerCount(document)', '1');
  30     document.onscroll = function() { }
  31     shouldBe('window.internals.scrollEventHandlerCount(document)', '1');
  32     document.onscroll = null;
  33     shouldBe('window.internals.scrollEventHandlerCount(document)', '0');
  34 })();
  35
  36 debug('Test that nested Documents\' scroll handlers are properly tracked in their parent Document.');
  37 (function() {
  38     var iframe = document.createElement('iframe');
  39     var scrolltarget = document.getElementById('scrolltarget');
  40     scrolltarget.onscroll = function() {};
  41
  42     shouldBe('window.internals.scrollEventHandlerCount(document)', '1');
  43
  44     scrolltarget.appendChild(iframe);
  45
  46     nestedDocument = iframe.contentWindow.document;
  47     nestedDocument.open('text/html', 'replace');
  48     nestedDocument.write('<!DOCTYPE html>\n<script>\ndocument.onscroll=function(){};\n</' + 'script>\n');
  49     shouldBe('window.internals.scrollEventHandlerCount(nestedDocument)', '2');
  50     shouldBe('window.internals.scrollEventHandlerCount(document)', '2');
  51
  52     nestedDocument.write('<script>document.onscroll=undefined</' + 'script>\n');
  53     shouldBe('window.internals.scrollEventHandlerCount(nestedDocument)', '1');
  54     shouldBe('window.internals.scrollEventHandlerCount(document)', '1');
  55
  56     nestedDocument.close();
  57
  58     scrolltarget.removeChild(iframe);
  59     shouldBe('window.internals.scrollEventHandlerCount(document)', '1');
  60     scrolltarget.onscroll = undefined;
  61 })();
  62
  63 debug('Test that detaching a nested Document with handlers works properly.');
  64 (function() {
  65     var iframe = document.createElement('iframe');
  66     var scrolltarget = document.getElementById('scrolltarget');
  67
  68     scrolltarget.appendChild(iframe);
  69
  70     nestedDocument = iframe.contentWindow.document;
  71     nestedDocument.open('text/html', 'replace');
  72     nestedDocument.write('<!DOCTYPE html>\n<script>\ndocument.onscroll=function(){};\n' +
  73                          'window.onscroll=function(){};</' + 'script>\n');
  74     shouldBe('window.internals.scrollEventHandlerCount(nestedDocument)', '2');
  75     shouldBe('window.internals.scrollEventHandlerCount(document)', '2');
  76
  77     nestedDocument.close();
  78     scrolltarget.removeChild(iframe);
  79     shouldBe('window.internals.scrollEventHandlerCount(document)', '0');
  80 })();
  81
  82 debug('Test moving event listeners from an unattached document to an attached one');
  83 (function() {
  84     doc = document.implementation.createHTMLDocument('');
  85     var div = doc.createElement('div');
  86     var childDiv = doc.createElement('div');
  87
  88     div.addEventListener('scroll', function() { });
  89     childDiv.addEventListener('scroll', function() { });
  90     div.appendChild(childDiv);
  91
  92     // Since we only track event handlers on documents that attached to a page,
  93     // |doc| should not have any registered handlers at this point.
  94     shouldBe('window.internals.scrollEventHandlerCount(doc)', '0');
  95     shouldBe('window.internals.scrollEventHandlerCount(document)', '0');
  96
  97     // Move the top level div into the current document. Both event handlers should
  98     // get registered.
  99     document.body.appendChild(div);
 100     shouldBe('window.internals.scrollEventHandlerCount(document)', '2');
 101
 102     // Removing the div from the document does not affect the event handler count.
 103     document.body.removeChild(div);
 104     shouldBe('window.internals.scrollEventHandlerCount(document)', '2');
 105
 106     // Once the divs are destroyed the handlers go away.
 107     div = null;
 108     childDiv = null;
 109     doc = null;
 110     gc();
 111     shouldBe('window.internals.scrollEventHandlerCount(document)', '0');
 112 })();
 113
 114 debug('Test moving event listeners from an attached document to an unattached one');
 115 (function() {
 116     var div = document.createElement('div');
 117     div.addEventListener('scroll', function() { });
 118     document.body.appendChild(div);
 119
 120     var iframe = document.createElement('iframe');
 121     div.appendChild(iframe);
 122     var nestedDocument = iframe.contentWindow.document;
 123     nestedDocument.open('text/html', 'replace');
 124     nestedDocument.write('<!DOCTYPE html>\n<script>\ndocument.onscroll=function(){};\n' +
 125                          'window.onscroll=function(){};</' + 'script>\n');
 126     nestedDocument.close();
 127
 128     shouldBe('window.internals.scrollEventHandlerCount(document)', '3');
 129
 130     var unattachedDoc = document.implementation.createHTMLDocument('');
 131     unattachedDoc.body.appendChild(div);
 132     shouldBe('window.internals.scrollEventHandlerCount(document)', '0');
 133 })();
 134
 135 debug('Test moving a scroll event listener between documents belonging to the same page');
 136 (function() {
 137     var iframe = document.createElement('iframe');
 138     document.body.appendChild(iframe);
 139     var nestedDocument = iframe.contentWindow.document;
 140     nestedDocument.open('text/html', 'replace');
 141     nestedDocument.write('<!DOCTYPE html><div id=foo></div>');
 142     nestedDocument.close();
 143
 144     var element = frames[0].document.getElementById('foo');
 145     var listener = function() { }
 146     element.addEventListener('scroll', listener, false);
 147     frames[0].window.addEventListener('scroll', listener, false);
 148     shouldBe('window.internals.scrollEventHandlerCount(document)', '2');
 149
 150     document.body.appendChild(element);
 151     shouldBe('window.internals.scrollEventHandlerCount(document)', '2');
 152
 153     element.removeEventListener('scroll', listener, false);
 154     frames[0].window.removeEventListener('scroll', listener, false);
 155     shouldBe('window.internals.scrollEventHandlerCount(document)', '0');
 156 })();
 157
 158 debug('Test addEventListener/removeEventListener on the window.');
 159 (function() {
 160     var listener = function() { }
 161
 162     shouldBe('window.internals.scrollEventHandlerCount(document)', '0');
 163     window.addEventListener('scroll', listener, true);
 164     shouldBe('window.internals.scrollEventHandlerCount(document)', '1');
 165     window.addEventListener('scroll', listener, false);
 166     shouldBe('window.internals.scrollEventHandlerCount(document)', '2');
 167     window.removeEventListener('scroll', listener, true);
 168     shouldBe('window.internals.scrollEventHandlerCount(document)', '1');
 169
 170     // Try removing the capturing listener again.
 171     window.removeEventListener('scroll', listener, true);
 172     shouldBe('window.internals.scrollEventHandlerCount(document)', '1');
 173
 174     window.removeEventListener('scroll', listener, false);
 175     shouldBe('window.internals.scrollEventHandlerCount(document)', '0');
 176 })();
 177
 178 debug('Test setting onscroll on the window.');
 179 (function() {
 180     shouldBe('window.internals.scrollEventHandlerCount(document)', '0');
 181     window.onscroll = function() { }
 182     shouldBe('window.internals.scrollEventHandlerCount(document)', '1');
 183     window.onscroll = function() { }
 184     shouldBe('window.internals.scrollEventHandlerCount(document)', '1');
 185     window.onscroll = null;
 186     shouldBe('window.internals.scrollEventHandlerCount(document)', '0');
 187 })();
 188 </script>
 189 </body>