<!
DOCTYPE HTML>
<
title>Testcase, bug 1209603</
title>
<
style>
p {
font-size: 2
em;
/* ensure font-size dependency in the margin struct; this is also in
the UA
style sheet, but repeated here for clarity */
margin: 1
em 0;
}
</
style>
<
div style=
"font-size: 20px"><p id=
"a">Should be 40px
font size.</p></
div>
<
script>
var a = document.getElementById(
"a");
// force computation of the margin struct on A (caching in rule tree)
getComputedStyle(a,
"").marginTop;
</
script>
<!-- will dynamically change font-size to 10px later;
also needs to be different from 20px now to avoid sibling-sharing -->
<
div style=
"font-size: 30px"><p id=
"b">Should be 20px
font size.</p></
div>
<
script>
// Note that A and B share rule nodes, and note that the margin struct
// has been conditionally (on
font size) cached on their shared rule node.
var b = document.getElementById(
"b");
// force ComputedStyle construction and computation of the
font struct on
// B
's parent
getComputedStyle(b.parentNode,
"").fontSize;
// force ComputedStyle construction (and computation of the color
// struct) on B, but not the margin struct or
font struct
getComputedStyle(b,
"").color;
// restyle B and flush
b.parentNode.
style.fontSize =
"10px";
getComputedStyle(b,
"").marginTop;
// This flush will call CalcStyleDifference on B, which will find no
// cached
font struct on the old context, but which will find a
// cached margin struct on the rule node.
</
script>
