Adding upstream version 115.7.0esr.upstream/115.7.0esr

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 57 insertions, 0 deletions

diff --git a/docs/performance/memory/DOM_allocation_example.md b/docs/performance/memory/DOM_allocation_example.md
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+# DOM allocation example
+
+This article describes a very simple web page that we\'ll use to
+illustrate some features of the Memory tool.
+
+You can try out the site at
+<https://mdn.github.io/performance-scenarios/dom-allocs/alloc.html>.
+
+It just contains a script that creates a large number of DOM nodes:
+
+```js
+var toolbarButtonCount = 20;
+var toolbarCount = 200;
+
+function getRandomInt(min, max) {
+    return Math.floor(Math.random() * (max - min + 1)) + min;
+}
+
+function createToolbarButton() {
+  var toolbarButton = document.createElement("span");
+  toolbarButton.classList.add("toolbarbutton");
+  // stop Spidermonkey from sharing instances
+  toolbarButton[getRandomInt(0,5000)] = "foo";
+  return toolbarButton;
+}
+
+function createToolbar() {
+  var toolbar = document.createElement("div");
+  // stop Spidermonkey from sharing instances
+  toolbar[getRandomInt(0,5000)] = "foo";
+  for (var i = 0; i < toolbarButtonCount; i++) {
+    var toolbarButton = createToolbarButton();
+    toolbar.appendChild(toolbarButton);
+  }
+  return toolbar;
+}
+
+function createToolbars() {
+  var container = document.getElementById("container");
+  for (var i = 0; i < toolbarCount; i++) {
+    var toolbar = createToolbar();
+    container.appendChild(toolbar);
+  }
+}
+
+createToolbars();
+```
+
+A simple pseudocode representation of how this code operates looks like
+this:
+
+    createToolbars()
+        -> createToolbar() // called 200 times, creates 1 DIV element each time
+           -> createToolbarButton() // called 20 times per toolbar, creates 1 SPAN element each time
+
+In total, then, it creates 200 `HTMLDivElement` objects, and 4000
+`HTMLSpanElement` objects.